FIELD
[0001] Embodiments described herein relate generally to a semiconductor light emitting device.
BACKGROUND
[0002] A structure is known in which a p-side electrode and an n-side electrode formed on
a surface of a semiconductor layer that includes a light emitting layer are on the
side opposite to the light extraction surface. In this structure, the degrees of freedom
of the configurations and layout of the electrodes are high because the electrodes
do not impede the light extraction from the light extraction surface. An appropriate
design of the configurations and layout of the electrodes is necessary because the
configurations and layout of the electrodes affect the electrical characteristics
and the luminous efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003]
FIG. 1 is a schematic plan view of a semiconductor light emitting device of a first
embodiment;
FIG. 2 is the A-A' cross-sectional view of FIG. 1;
FIG. 3 is the B-B' cross-sectional view of FIG. 1;
FIG. 4 to FIG. 8 are schematic plan views showing a method for manufacturing the semiconductor
light emitting device of the first embodiment;
FIG. 9A to FIG. 10B are schematic cross-sectional views showing a method for manufacturing
the semiconductor light emitting device of the first embodiment;
FIG. 11 is a schematic cross-sectional view of another semiconductor light emitting
device of the first embodiment;
FIG. 12 is a schematic plan view of a semiconductor light emitting device of a second
embodiment;
FIG. 13 is the C-C' cross-sectional view of FIG. 12;
FIG. 14 is the D-D' cross-sectional view of FIG. 12;
FIG. 15 to FIG. 17 are schematic plan views showing a method for manufacturing the
semiconductor light emitting device of the second embodiment;
FIG. 18A to FIG. 19B are schematic cross-sectional views showing a method for manufacturing
the semiconductor light emitting device of the second embodiment;
FIG. 20 is a schematic cross-sectional view of another semiconductor light emitting
device of the second embodiment;
FIG. 21A to FIG. 32B are schematic views showing a method for manufacturing the semiconductor
light emitting device of the third embodiment;
FIG. 33A to FIG. 34B are schematic views showing a method for manufacturing the semiconductor
light emitting device of the fourth embodiment;
FIG. 35 is a schematic plan view of another semiconductor light emitting device of
the third, fourth and fifth embodiments;
FIG. 36A to FIG. 47B are schematic views showing a method for manufacturing the semiconductor
light emitting device of the fifth embodiment;
FIG. 48 is a schematic cross-sectional view of a semiconductor light emitting device
of a sixth embodiment;
FIG. 49A to FIG. 50C are schematic plan views of the semiconductor light emitting
device of the sixth embodiment;
FIGS. 51A to 51D are schematic plan views of a semiconductor light emitting device
of a seventh embodiment; and
FIGS. 52A to 52D are schematic plan views of another semiconductor light emitting
device of the third embodiment.
DETAILED DESCRIPTION
[0004] According to one embodiment, a semiconductor light emitting device includes a first
semiconductor layer, a light emitting layer, a second semiconductor layer, a p-side
electrode, a plurality of n-side electrodes, a first insulating film, a p-side interconnect
unit, and an n-side interconnect unit. The first semiconductor layer has a first surface
and a second surface opposite to the first surface. The second surface has a p-side
region and a plurality of n-side regions. The light emitting layer is provided on
the p-side region. The second semiconductor layer is provided on the light emitting
layer. The p-side electrode is provided on the second semiconductor layer. The plurality
of n-side electrodes is provided respectively on the plurality of n-side regions.
The first insulating film is provided on the p-side electrode and on the n-side electrodes.
The p-side interconnect unit is provided on the first insulating film to connect to
the p-side electrode through a first via piercing the first insulating film. The n-side
interconnect unit is provided on the first insulating film to commonly connect to
the plurality of n-side electrodes through a second via piercing the first insulating
film. The plurality of n-side regions is separated from each other without being linked
at the second surface. The p-side region is provided around each of the n-side regions
at the second surface.
[0005] Embodiments will now be described with reference to the drawings. Similar components
in the drawings are marked with like reference numerals.
First embodiment
[0006] FIG. 1 is a schematic plan view of a semiconductor light emitting device 1 of the
first embodiment.
[0007] FIG. 2 is the A-A' cross-sectional view of FIG. 1.
[0008] FIG. 3 is the B-B' cross-sectional view of FIG. 1.
[0009] FIG. 1 shows a second surface side which is the side opposite to a first surface
15a of a semiconductor layer 15 and shows the planar layout of the components other
than the insulating films and the resin layers.
[0010] As shown in FIGS. 2 and 3, the semiconductor light emitting device 1 includes the
semiconductor layer 15. The semiconductor layer 15 includes a first semiconductor
layer 11, a second semiconductor layer 12, and a light emitting layer 13. The first
semiconductor layer 11, the second semiconductor layer 12, and the light emitting
layer 13 are nitride semiconductors of In
xAl
yGa
1-x-yN (0≤
x≤1, 0≤
y≤1, and
x+
y≤1). "Nitride semiconductor" further includes components including an impurity added
to control the conductivity type.
[0011] The first semiconductor layer 11 has the first surface 15a and the second surface
provided on the side opposite to the first surface 15a. The second surface has a p-side
region 14a and n-side regions 14b. The first semiconductor layer 11 includes, for
example, a foundation buffer layer and an n-type GaN layer.
[0012] The light emitting layer (the active layer) 13 is provided on the p-side region 14a
at the second surface of the first semiconductor layer 11. The light emitting layer
13 has, for example, an InGaN multiple quantum well structure in which multiple pairs
of an InGaN well layer and a GaN or InGaN barrier layer are stacked and emits blue
light, violet light, bluish-violet light, ultraviolet light, etc.
[0013] The second semiconductor layer 12 including a p-type GaN layer is provided on the
light emitting layer 13. The light emitting layer 13 is provided between the first
semiconductor layer 11 and the second semiconductor layer 12. The light emitting layer
13 and the second semiconductor layer 12 are not provided in the n-side regions 14b
at the second surface of the first semiconductor layer 11.
[0014] The n-side regions 14b are formed by the front surface of the first semiconductor
layer 11 being exposed by selectively removing a portion of the light emitting layer
13 and the second semiconductor layer 12 formed on the entire surface of the second
surface of the first semiconductor layer 11.
[0015] The first surface 15a of the first semiconductor layer 11 functions as the main extraction
surface of the light; and the light emitted by the light emitting layer 13 is emitted
outside the semiconductor layer 15 mainly from the first surface 15a. The p-side electrode,
the n-side electrodes, the p-side interconnect unit, and the n-side interconnect unit
described below are provided on the side opposite to the first surface 15a.
[0016] A p-side electrode 16a is provided on the second semiconductor layer 12. The p-side
electrode 16a has an ohmic contact with the second semiconductor layer 12. N-side
electrodes 17a are provided in the n-side regions 14b at the second surface of the
first semiconductor layer 11. The n-side electrodes 17a have ohmic contacts with the
first semiconductor layer 11.
[0017] The p-side electrode 16a and the n-side electrodes 17a are provided on the same surface
side which is the side opposite to the first surface 15a which is the main light extraction
surface of the semiconductor layer 15; the p-side electrode 16a is provided on the
region including the light emitting layer 13; and the n-side electrodes 17a are provided
on the n-side regions 14b not including the light emitting layer 13.
[0018] A p-side pad 16b covering the p-side electrode 16a is provided on the front surface
and the side surface of the p-side electrode 16a. The p-side electrode 16a includes
a material having a high reflectance for the light emitted by the light emitting layer
13, e.g., Ag, a Ag alloy, etc. The p-side pad 16b includes a material that protects
the p-side electrode 16a from corroding, e.g., Al, Ti, Ni, Au, etc.
[0019] N-side pads 17b covering the n-side electrodes 17a are provided on the front surfaces
and the side surfaces of the n-side electrodes 17a. The n-side electrodes 17a include,
for example, at least one selected from nickel (Ni), gold (Au), and rhodium (Rh) that
is capable of forming an alloy with the gallium (Ga) included in the semiconductor
layer 15. The n-side pads 17b include a material that protects the n-side electrodes
17a from corroding, e.g., Al, Ti, Ni, Au, etc.
[0020] FIG. 4 shows the planar layout of the p-side region 14a, the n-side regions 14b,
the p-side electrode 16a, the p-side pad 16b, the n-side electrodes 17a, and the n-side
pads 17b on the second surface.
[0021] The multiple n-side regions 14b inside the p-side region 14a which is spread over
the entire second surface are uniformly interspersed. Each of the n-side regions 14b
is formed as, for example, a circular region. The multiple n-side regions 14b are
separated from each other without being linked at the second surface; and the p-side
region 14a is provided around each of the n-side regions 14b at the second surface.
[0022] The n-side electrodes 17a are provided respectively on the multiple n-side regions
14b. The multiple n-side electrodes 17a are uniformly interspersed in a dot configuration
or an island configuration on the second surface.
[0023] As shown in FIG. 2, the second semiconductor layer 12 is provided around each of
the n-side electrodes 17a and n-side pads 17b. The n-side regions 14b of the first
semiconductor layer 11, the n-side electrodes 17a provided on the n-side regions 14b,
and the n-side pads 17b covering the n-side electrodes 17a are partitioned by the
light emitting layer 13 and the second semiconductor layer 12 stacked on the light
emitting layer 13 and are separated into a plurality on the second surface.
[0024] As shown in FIGS. 2 and 3, a first insulating film (hereinbelow, called simply the
insulating film) 18 is provided on the second surface side of the semiconductor layer
15. The insulating film 18 covers the n-side regions 14b, the front surface of the
second semiconductor layer 12, the side surface of the second semiconductor layer
12, the side surface of the light emitting layer 13, the p-side pad 16b, and the n-side
pads 17b.
[0025] There are cases where another insulating film (e.g., a silicon oxide film) is provided
between the insulating film 18 and the semiconductor layer 15. The insulating film
18 is, for example, a resin such as polyimide, etc., having excellent patternability
of fine openings. Or, an inorganic film such as a silicon oxide film, a silicon nitride
film, etc., may be used as the insulating film 18.
[0026] An n-side interconnect layer (a first n-side interconnect layer) 22 shown in FIG.
2 and a p-side interconnect layer (a first p-side interconnect layer) 21 shown in
FIG. 3 are provided on the front surface of the insulating film 18 on the side opposite
to the semiconductor layer 15.
[0027] As shown in FIG. 2, n-side vias 22a are provided respectively on the n-side pads
17b by piercing the insulating film 18. The n-side interconnect layer 22 is electrically
connected to each of the n-side pads 17b and n-side electrodes 17a by means of each
of the n-side vias 22a.
[0028] As shown in FIG. 3, multiple p-side vias 21a are provided on the p-side pad 16b by
piercing the insulating film 18. The p-side interconnect layer 21 is electrically
connected to the p-side pad 16b and the p-side electrode 16a by means of the multiple
first p-side vias 21a.
[0029] FIG. 5 shows the planar layout of the n-side vias 22a and the p-side vias 21a; and
FIG. 6 is a plan view in which the n-side interconnect layers 22 and the p-side interconnect
layers 21 are overlaid on FIG. 5.
[0030] The multiple (in FIG. 6, e.g., three) n-side electrodes 17a provided to be separated
on the second surface are connected respectively by means of the n-side vias 22a to
one common n-side interconnect layer 22 extending in a first direction X in FIG. 6.
As shown in FIG. 2, the one n-side interconnect layer 22 straddles above the p-side
electrode 16a and the p-side pad 16b with the insulating film 18 interposed to commonly
connect to the multiple n-side electrodes 17a.
[0031] The n-side interconnect layer 22 is multiply provided; and each of the n-side interconnect
layers 22 extends in the first direction X in FIG. 6. The p-side interconnect layers
21 are provided in the region between the n-side interconnect layers 22 adjacent to
each other in a second direction Y orthogonal to the first direction X.
[0032] The multiple n-side interconnect layers 22 and the multiple p-side interconnect layers
21 are arranged alternately to be separated from each other in the second direction
Y on the insulating film 18.
[0033] As shown in FIG. 2 and FIG. 3, an insulating film 41 is provided on the insulating
film 18, on the n-side interconnect layers 22, and on the p-side interconnect layers
21. The insulating film 41 is a material similar to that of the insulating film 18
such as, for example, an inorganic insulating film such as a silicon oxide film, a
resin film such as polyimide, etc. The insulating film 41 covers the n-side interconnect
layers 22 and the p-side interconnect layers 21.
[0034] An n-side interconnect layer (a second n-side interconnect layer) 32 and a p-side
interconnect layer (a second p-side interconnect layer) 31 are provided on the insulating
film 41.
[0035] As shown in FIG. 2, n-side vias 33 are provided on the n-side interconnect layers
22 by piercing the insulating film 41. The n-side interconnect layer 32 is electrically
connected to the n-side interconnect layers 22 by means of the n-side vias 33.
[0036] As shown in FIG. 3, p-side vias 34 are provided on the p-side interconnect layers
21 by piercing the insulating film 41. The p-side interconnect layer 31 is electrically
connected to the p-side interconnect layers 21 by means of the p-side vias 34.
[0037] FIG. 7 shows the planar layout of the n-side vias 33 and the p-side vias 34; and
FIG. 8 is a plan view in which the n-side interconnect layer 32 and the p-side interconnect
layer 31 are overlaid on FIG. 7.
[0038] One n-side via 33 is provided for one n-side interconnect layer 22. Accordingly,
the multiple n-side vias 33 are arranged in the second direction Y to correspond to
the number of the n-side interconnect layers 22.
[0039] One p-side via 34 is provided for one p-side interconnect layer 21. Accordingly,
the multiple p-side vias 34 are arranged in the second direction Y to correspond to
the number of the p-side interconnect layers 21.
[0040] The multiple n-side vias 33 and the multiple p-side vias 34 are provided to be divided
into the left and right with respect to the center in the first direction X. In FIGS.
7 and 8, the n-side vias 33 are provided in the region on the left side of the center
in the first direction X; and the p-side vias 34 are provided in the region on the
right side of the center in the first direction X.
[0041] The n-side interconnect layer 32 spreads in the region on the left side of the center
in the first direction X in FIG. 8. The multiple n-side interconnect layers 22 are
connected to one common n-side interconnect layer 32 by means of the n-side vias 33.
[0042] The p-side interconnect layer 31 spreads in the region on the right side of the center
in the first direction X in FIG. 8. The multiple p-side interconnect layers 21 are
connected to one common p-side interconnect layer 31 by means of the p-side vias 34.
[0043] The n-side interconnect layer 32 and the p-side interconnect layer 31 spread to be
divided into the left and right with the same surface area with the center in the
first direction X interposed. The n-side interconnect layer 32 and the p-side interconnect
layer 31 are separated from each other on the insulating film 41.
[0044] As shown in FIGS. 2 and 3, a p-type metal pillar 23 is provided on the p-side interconnect
layer 31. The p-side interconnect layers 21, the p-side interconnect layer 31, and
the p-type metal pillar 23 are included in the p-side interconnect unit of the embodiment.
[0045] An n-side metal pillar 24 is provided on the n-side interconnect layer 32. The n-side
interconnect layers 22, the n-side interconnect layer 32, and the n-side metal pillar
24 are included in the n-side interconnect unit of the embodiment.
[0046] For example, a resin layer 25 is stacked on the insulating film 41 as a second insulating
film. The resin layer 25 covers the periphery of the n-side interconnect layer 32,
the periphery of the n-side metal pillar 24, the periphery of the p-side interconnect
layer 31, and the periphery of the p-type metal pillar 23. The resin layer 25 is filled
between the p-side interconnect layer 31 and the n-side interconnect layer 32 and
between the p-type metal pillar 23 and the n-side metal pillar 24.
[0047] The side surface of the p-type metal pillar 23 and the side surface of the n-side
metal pillar 24 are covered with the resin layer 25. The surface of the p-type metal
pillar 23 on the side opposite to the p-side interconnect layer 31 is exposed from
the resin layer 25 and functions as a p-side external terminal 23a. The surface of
the n-side metal pillar 24 on the side opposite to the n-side interconnect layer 32
is exposed from the resin layer 25 and functions as an n-side external terminal 24a.
[0048] The p-side external terminal 23a and the n-side external terminal 24a are bonded
to pads formed in a not-shown mounting substrate via solder, etc.
[0049] The distance between the p-side external terminal 23a and the n-side external terminal
24a exposed at the same surface (in FIGS. 2 and 3, the upper surface) of the resin
layer 25 is greater than the distance between the p-side interconnect layer 31 and
the n-side interconnect layer 32 on the insulating film 41. The distance between the
p-side external terminal 23a and the n-side external terminal 24a is greater than
the distance between the p-side interconnect layers 21 and the n-side interconnect
layers 22 on the insulating film 18.
[0050] The p-side external terminal 23a and the n-side external terminal 24a are separated
by a distance such that the p-side external terminal 23a and the n-side external terminal
24a are not shorted to each other by the solder when mounting to the mounting substrate.
[0051] The p-side interconnect layers 21 can be proximal to the n-side interconnect layers
22 to the limits of the processes; and the surface area of the p-side interconnect
layer 31 can be increased. Also, the p-side interconnect layer 31 can be proximal
to the n-side interconnect layer 32 to the limits of the processes. As a result, the
surface area of the p-side interconnect layers 21 and the p-side interconnect layer
31 can be large; and the current distribution and the heat dissipation can be improved.
[0052] The surface area of the p-side interconnect layers 21 contacting the p-side pad 16b
by means of the multiple p-side vias 21a is greater than the surface area of the n-side
interconnect layers 22 contacting the n-side pads 17b by means of the multiple n-side
vias 22a. Therefore, the current distribution to the light emitting layer 13 can be
improved; and the heat dissipation of the heat of the light emitting layer 13 can
be improved.
[0053] The surface area of the n-side interconnect layers 22 spreading on the insulating
film 18 is greater than the surface area where the n-side interconnect layers 22 connect
to the n-side pads 17b by means of the n-side vias 22a.
[0054] According to the embodiment, a high light output can be obtained by the light emitting
layer 13 spreading over the region that is larger than the n-side electrodes 17a.
The n-side electrodes 17a provided in the n-side regions 14b that are narrower than
the region including the light emitting layer 13 are drawn out to the side opposite
to the light extraction surface (the first surface 15a) as the n-side interconnect
layers 22 that have larger surface areas.
[0055] As shown in FIG. 2, the first semiconductor layer 11 is electrically connected to
the n-side external terminal 24a via the n-side electrodes 17a, the n-side pads 17b,
the n-side vias 22a, the n-side interconnect layers 22, the n-side vias 33, the n-side
interconnect layer 32, and the n-side metal pillar 24.
[0056] As shown in FIG. 3, the second semiconductor layer 12 is electrically connected to
the p-side external terminal 23a via the p-side electrode 16a, the p-side pad 16b,
the p-side vias 21a, the p-side interconnect layers 21, the p-side vias 34, the p-side
interconnect layer 31, and the p-type metal pillar 23.
[0057] The p-type metal pillar 23 is thicker than the p-side interconnect layers 21 and
thicker than the p-side interconnect layer 31. The n-side metal pillar 24 is thicker
than the n-side interconnect layers 22 and thicker than the n-side interconnect layer
32. The thicknesses of the p-type metal pillar 23, the n-side metal pillar 24, and
the resin layer 25 are thicker than the semiconductor layer 15. Here, "thickness"
refers to the thickness in the vertical direction in FIGS. 2 and 3.
[0058] The thicknesses of the p-type metal pillar 23 and the n-side metal pillar 24 are
thicker than the thickness of the chip which includes the semiconductor layer 15,
the p-side electrode 16a, the p-side pad 16b, the n-side electrodes 17a, and the n-side
pads 17b. The aspect ratios (the ratios of the thickness to the planar size) of the
metal pillars 23 and 24 are not limited to being 1 or more and may be smaller than
1. In other words, the thicknesses of the metal pillars 23 and 24 may be less than
the planar sizes of the metal pillars 23 and 24.
[0059] According to the embodiment, even if the substrate used to form the semiconductor
layer 15 is removed, the semiconductor layer 15 can be stably supported by the support
body including the p-type metal pillar 23, the n-side metal pillar 24, and the resin
layer 25; and the mechanical strength of the semiconductor light emitting device 1
can be increased.
[0060] Copper, gold, nickel, silver, etc., may be used as the materials of the p-side vias
21a, the p-side interconnect layers 21, the p-side vias 34, the p-side interconnect
layer 31, the p-type metal pillar 23, the n-side vias 22a, the n-side interconnect
layers 22, the n-side vias 33, the n-side interconnect layer 32, and the n-side metal
pillar 24. Among these, good thermal conductivity, high migration resistance, and
excellent adhesion with insulating materials are obtained when copper is used.
[0061] The resin layer 25 reinforces the p-type metal pillar 23 and the n-side metal pillar
24. It is desirable for the resin layer 25 to have a coefficient of thermal expansion
near to or the same as that of the mounting substrate. Examples of such a resin layer
25 include, for example, an epoxy resin, a silicone resin, a fluorocarbon resin, etc.
[0062] The stress applied to the semiconductor layer 15 via the solder in the state in which
the semiconductor light emitting device 1 is mounted to the mounting substrate via
the p-side external terminal 23a and the n-side external terminal 24a can be relaxed
by being absorbed by the p-type metal pillar 23 and the n-side metal pillar 24.
[0063] The substrate used when forming the semiconductor layer 15 is removed from the first
surface 15a. Therefore, the semiconductor light emitting device 1 can be thinner.
[0064] As shown in FIG. 11, a phosphor layer 50 can be provided on the first surface 15a.
The phosphor layer 50 includes a transparent resin 51 as a transparent medium and
a phosphor 52 having a multiple particle configuration dispersed in the transparent
resin 51.
[0065] The transparent resin 51 is transmissive to the light emitted by the light emitting
layer 13 and the light emitted by the phosphor 52 and may include, for example, a
silicone resin, an acrylic resin, a phenyl resin, etc.
[0066] The phosphor 52 is capable of absorbing the emitted light (the excitation light)
of the light emitting layer 13 and emitting wavelength-converted light. Therefore,
the semiconductor light emitting device of the embodiment is capable of emitting a
mixed light of the light emitted by the light emitting layer 13 and the wavelength-converted
light of the phosphor 52.
[0067] For example, white, lamp, etc., can be obtained as a mixed color of the blue light
of the light emitting layer 13 which is the InGaN-based material and the yellow light
which is the wavelength-converted light of the phosphor 52 in the case where the phosphor
52 is a yellow phosphor that emits yellow light. The phosphor layer 50 may have a
configuration including multiple types of phosphors (e.g., a red phosphor that emits
red light and a green phosphor that emits green light).
[0068] In the semiconductor light emitting device 1 of the embodiment, the p-side electrode
16a and the n-side electrodes 17a are provided on the second surface on the side opposite
to the first surface 15a which is the main extraction surface of the light. Accordingly,
the light extraction from the first surface 15a is not impeded by the electrodes.
The p-side electrode 16a is provided on the region including the light emitting layer
13. The n-side electrodes 17a are provided on the first semiconductor layer 11 not
including the light emitting layer 13.
[0069] According to the embodiment, the contact surface between the n-side electrodes 17a
and the first semiconductor layer 11, i.e., the n-side regions 14b at the second surface
of the first semiconductor layer 11, has a uniform disposition in the second surface
in a dot configuration. Therefore, a uniform current distribution in the surface direction
of the light emitting layer 13 can be realized while increasing the light emission
surface area by reducing the region not including the light emitting layer 13.
[0070] Holes are supplied from the p-side electrode 16a to the light emitting layer 13 via
the contact surface between the p-side electrode 16a and the second semiconductor
layer 12; and electrons are supplied from the n-side electrodes 17a to the light emitting
layer 13 via the contact surface between the first semiconductor layer 11 and the
n-side electrodes 17a. The current density of the light emitting layer 13 easily increases
in the region proximal to the n-side electrodes 17a.
[0071] According to the embodiment, the p-side region 14a and the light emitting layer 13
exist completely around the n-side regions 14b and the n-side electrodes 17a. Accordingly,
as schematically illustrated by the broken lines in FIG. 4, the current from one n-side
electrode 17a can spread 360 degrees around the one n-side electrode 17a; and the
current can be supplied efficiently to the entire region of the light emitting layer
13. Accordingly, according to the embodiment, the entire region of the light emitting
layer 13 can be efficiently caused to emit light.
[0072] Although the multiple n-side electrodes 17a are separated from each other on the
second surface of the first semiconductor layer 11, the multiple n-side electrodes
17a are connected to a common n-side interconnect unit on the side opposite to the
light extraction surface (the first surface 15a) by which the mounting to the mounting
substrate is performed. Therefore, the same potential can be provided to the multiple
n-side electrodes 17a by a simple configuration without performing wire bonding to
each of the multiple n-side electrodes 17a.
[0073] A method for manufacturing the semiconductor light emitting device 1 of the first
embodiment will now be described with reference to FIG. 4 to FIG. 10B.
[0074] FIG. 9A is the A-A' cross section of FIG. 4; and FIG. 9B is the B-B' cross section
of FIG. 4.
[0075] The semiconductor layer 15 is formed on a substrate 10. First, the first semiconductor
layer 11 is formed on the major surface of the substrate 10; the light emitting layer
13 is formed on the first semiconductor layer 11; and the second semiconductor layer
12 is formed on the light emitting layer 13.
[0076] Crystal growth of the semiconductor layer 15 which is a nitride semiconductor of
In
xAl
yGa
1-x-yN (0≤
x≤1, 0≤
y≤1, and
x+
y≤1) may be performed by, for example, MOCVD (metal organic chemical vapor deposition)
on a sapphire substrate. Or, a silicon substrate may be used as the substrate 10.
[0077] The semiconductor layer 15 is formed on the entire surface of the substrate 10. Subsequently,
a portion of the first semiconductor layer 11 is exposed by removing a portion of
the light emitting layer 13 and the second semiconductor layer 12 as shown in FIG.
9A by, for example, RIE (Reactive Ion Etching) using a not-shown resist. The first
semiconductor layer 11 is selectively exposed in a dot configuration or an island
configuration.
[0078] The regions where the first semiconductor layer 11 is exposed are the n-side regions
14b which do not include the light emitting layer 13 and the second semiconductor
layer 12. The region where the second semiconductor layer 12 and the light emitting
layer 13 are left is the p-side region 14a.
[0079] The n-side electrodes 17a and the n-side pads 17b are formed on the n-side regions
14b. The p-side electrode 16a and the p-side pad 16b are formed on the front surface
of the second semiconductor layer 12 of the p-side region 14a.
[0080] For example, a silicon nitride film and/or a silicon oxide film may be formed by
CVD (chemical vapor deposition) as a passivation film on the end surface (the side
surface) of the light emitting layer 13 between the p-side pad 16b and the n-side
pads 17b.
[0081] Then, after covering all of the exposed portions on the major surface of the substrate
10 with the insulating film 18 shown in FIGS. 10A and 10B, first openings 18a and
second openings 18b are made selectively in the insulating film 18 by patterning the
insulating film 18 by etching. FIGS. 10A and 10B correspond to the cross sections
of FIGS. 9A and 9B, respectively.
[0082] As shown in FIG. 10B, the first openings 18a are multiply formed; and each of the
first openings 18a reaches the p-side pad 16b. As shown in FIG. 10A, the second openings
18b are made respectively on the multiple n-side pads 17b; and the second openings
18b respectively reach the n-side pads 17b.
[0083] FIG. 10A shows a cross section along the first direction X of FIG. 4; and the first
openings 18a are not made on the p-side pad 16b between the n-side regions 14b adjacent
to each other in the first direction X. Accordingly, the p-side vias 21a filled into
the first openings 18a are not formed on the p-side pad 16b between the n-side regions
14b adjacent to each other in the first direction X.
[0084] An organic material such as, for example, photosensitive polyimide, benzocyclobutene,
etc., may be used as the insulating film 18. In such a case, direct exposure and developing
of the insulating film 18 are possible without using a resist.
[0085] Or, an inorganic film such as a silicon nitride film, a silicon oxide film, etc.,
may be used as the insulating film 18. In the case where the insulating film 18 is
the inorganic film, the first openings 18a and the second openings 18b are made by
etching after a resist formed on the insulating film 18 is patterned.
[0086] Then, Cu electroplating is performed using a not-shown metal film as a seed metal
(a current path) after forming the metal film on the front surface of the insulating
film 18, the inner walls (the side walls and the bottom portions) of the first openings
18a, and the inner walls (the side walls and the bottom portions) of the second openings
18b.
[0087] Thereby, as shown in FIGS. 2, 3, and 5, the p-side vias 21a are formed inside the
first openings 18a; the n-side vias 22a are formed inside the second openings 18b;
and the p-side interconnect layers 21 and the n-side interconnect layers 22 are formed
on the insulating film 18. The p-side vias 21a, the n-side vias 22a, the p-side interconnect
layers 21, and the n-side interconnect layers 22 are made of, for example, a copper
material formed simultaneously by plating using a not-shown plating resist.
[0088] Then, as shown in FIGS. 2 and 3, the insulating film 41 is formed on the p-side interconnect
layers 21 and on the n-side interconnect layers 22. Continuing, similarly to the interconnect
units of the first layer including the p-side vias 21a, the n-side vias 22a, the p-side
interconnect layers 21, and the n-side interconnect layers 22 described above, the
interconnect units of the second layer including the p-side vias 34, the n-side vias
33, the p-side interconnect layer 31, and the n-side interconnect layer 32 shown in
FIGS. 2, 3, 7, and 8 are formed by Cu electroplating. Cu electroplating also is used
to form the p-type metal pillar 23 on the p-side interconnect layer 31 and to form
the n-side metal pillar 24 on the n-side interconnect layer 32.
[0089] After forming the p-type metal pillar 23 and the n-side metal pillar 24, the resin
layer 25 is stacked on the insulating film 41. The resin layer 25 covers the p-side
interconnect layer 31, the n-side interconnect layer 32, the p-type metal pillar 23,
and the n-side metal pillar 24.
[0090] Then, the substrate 10 described above that is used to form the semiconductor layer
15 is removed. In the case where the substrate 10 is the sapphire substrate, the substrate
10 can be removed by, for example, laser lift-off. Specifically, laser light is irradiated
from the back surface side of the substrate 10 toward the first semiconductor layer
11. The substrate 10 is transmissive to the laser light; and the laser light has a
wavelength in the absorption region of the first semiconductor layer 11.
[0091] When the laser light reaches the interface between the substrate 10 and the first
semiconductor layer 11, the first semiconductor layer 11 proximal to the interface
decomposes by absorbing the energy of the laser light. The first semiconductor layer
11 decomposes into gallium (Ga) and nitrogen gas. A micro gap is made between the
substrate 10 and the first semiconductor layer 11 by this decomposition reaction;
and the substrate 10 and the first semiconductor layer 11 separate.
[0092] The irradiation of the laser light is performed over the entire wafer by performing
multiply for every set region; and the substrate 10 is removed.
[0093] In the case where the substrate 10 is the silicon substrate, the substrate 10 can
be removed by etching.
[0094] Because the stacked body described above formed on the major surface of the substrate
10 is reinforced by the p-type metal pillar 23, the n-side metal pillar 24, and the
resin layer 25 that are thicker than the semiconductor layer 15, it is possible to
maintain the wafer state even in the case where there is no substrate 10.
[0095] The resin layer 25 and the metals included in the p-type metal pillar 23 and the
n-side metal pillar 24 are materials more flexible than the semiconductor layer 15.
The semiconductor layer 15 is supported by such a flexible support body. Therefore,
destruction of the semiconductor layer 15 can be avoided even in the case where the
large internal stress generated in the epitaxial growth of the semiconductor layer
15 on the substrate 10 is relieved all at once when peeling the substrate 10.
[0096] The first surface 15a of the semiconductor layer 15, from which the substrate 10
is removed, is cleaned. For example, the gallium (Ga) adhered to the first surface
15a is removed using dilute hydrofluoric acid, etc.
[0097] Subsequently, wet etching of the first surface 15a is performed using, for example,
a KOH (potassium hydroxide) aqueous solution, TMAH (tetramethylammonium hydroxide),
etc. Thereby, an unevenness is formed in the first surface 15a due to the difference
of the etching rates that depend on the crystal plane orientation. Or, the unevenness
may be formed in the first surface 15a by performing etching after the patterning
using the resist. The light extraction efficiency can be increased by the unevenness
being formed in the first surface 15a.
[0098] If necessary, the phosphor layer 50 shown in FIG. 11 is formed on the first surface
15a. The liquid transparent resin 51 into which the phosphor 52 is dispersed is thermally
cured after being supplied onto the first surface 15a by a method such as, for example,
printing, potting, molding, compression molding, etc.
[0099] Subsequently, singulation into the multiple semiconductor light emitting devices
1 is performed by cutting the stacked body recited above. For example, the cutting
is performed using a dicing blade. Or, the cutting may be performed using laser irradiation.
[0100] The semiconductor light emitting device 1 that is singulated may have a single-chip
structure including one semiconductor layer 15 or may have a multi-chip structure
including multiple semiconductor layers 15.
[0101] Because each of the processes described above until the dicing is performed can be
performed collectively in the wafer state, it is unnecessary to perform the interconnects
and the packaging for every singulated individual device; and it becomes possible
to drastically reduce the production costs. In other words, the interconnects and
the packaging are already complete in the singulated state. Therefore, the productivity
can be increased; and as a result, price reductions become easy.
Second embodiment
[0102] FIG. 12 is a schematic plan view of a semiconductor light emitting device 2 of a
second embodiment.
[0103] FIG. 13 is the C-C' cross-sectional view of FIG. 12.
[0104] FIG. 14 is the D-D' cross-sectional view of FIG. 12.
[0105] The semiconductor light emitting device 2 of the second embodiment also includes
the semiconductor layer 15; and the semiconductor layer 15 includes the first semiconductor
layer 11, the second semiconductor layer 12, and the light emitting layer 13 of In
xAl
yGa
1-x-yN (0≤
x≤1, 0≤
y≤1, and x+
y≤1).
[0106] FIG. 12 shows the second surface side which is the side opposite to the first surface
15a of the semiconductor layer 15 and shows the planar layout of the components other
than the insulating films and the resin layers.
[0107] In the second embodiment as well, the n-side electrodes 17a and the n-side pads 17b
are provided on the n-side regions 14b of the first semiconductor layer 11 not including
the light emitting layer 13 and the second semiconductor layer 12.
[0108] The light emitting layer 13 and the second semiconductor layer 12 are provided on
the p-side region 14a which is the region of the second surface of the first semiconductor
layer 11 other than the n-side regions 14b. The p-side electrode 16a and the p-side
pad 16b are provided on the front surface of the second semiconductor layer 12.
[0109] According to the second embodiment, the planar layout of the n-side regions 14b,
the n-side electrodes 17a provided on the n-side regions 14b, and the n-side pads
17b provided on the n-side regions 14b is different from that of the first embodiment.
[0110] FIG. 15 shows the planar layout of the p-side region 14a, the n-side regions 14b,
the p-side electrode 16a, the p-side pad 16b, the n-side electrodes 17a, and the n-side
pads 17b on the second surface.
[0111] Multiple (in the illustrations, e.g., three) n-side regions 14b are uniformly disposed
inside the p-side region 14a which is spread over the entire second surface. Each
of the n-side regions 14b is formed as a region having, for example, a rectangular
configuration. At the second surface, the multiple n-side regions 14b are separated
from each other without being linked; and the p-side region 14a is provided around
each of the n-side regions 14b.
[0112] The n-side electrodes 17a are provided respectively on the multiple n-side regions
14b. The multiple n-side electrodes 17a are formed in rectangular configurations on
the second surface.
[0113] As shown in FIG. 13, the second semiconductor layer 12 is provided around each of
the n-side electrodes 17a and n-side pads 17b. The n-side regions 14b of the first
semiconductor layer 11, the n-side electrodes 17a provided on the n-side regions 14b,
and the n-side pads 17b covering the n-side electrodes 17a are partitioned by the
light emitting layer 13 and the second semiconductor layer 12 stacked on the light
emitting layer 13 and are separated into a plurality on the second surface.
[0114] As shown in FIGS. 13 and 14, the insulating film 18 is provided on the second surface
side of the semiconductor layer 15. The insulating film 18 covers the n-side regions
14b, the front surface of the second semiconductor layer 12, the side surface of the
second semiconductor layer 12, the side surface of the light emitting layer 13, the
p-side pad 16b, and the n-side pads 17b.
[0115] There are cases where another insulating film (e.g., a silicon oxide film) is provided
between the insulating film 18 and the semiconductor layer 15. The insulating film
18 is, for example, a resin such as polyimide, etc., having excellent patternability
of fine openings. Or, an inorganic film such as a silicon oxide film, a silicon nitride
film, etc., may be used as the insulating film 18.
[0116] The second embodiment differs from the first embodiment in that the p-side interconnect
layer and the n-side interconnect layer having single-layer structures are provided
on the insulating film 18. The n-side interconnect layer 32 and the p-side interconnect
layer 31 are provided on the front surface of the insulating film 18 on the side opposite
to the semiconductor layer 15.
[0117] As shown in FIGS. 13 and 16, the n-side vias 22a are provided respectively on the
multiple n-side pads 17b by piercing the insulating film 18. The n-side interconnect
layer 32 is electrically connected to the n-side pads 17b and the n-side electrodes
17a by means of the n-side vias 22a.
[0118] As shown in FIGS. 14 and 16, the multiple p-side vias 21a are provided on the p-side
pad 16b by piercing the insulating film 18. The p-side interconnect layer 31 is electrically
connected to the p-side pad 16b and the p-side electrode 16a by means of the p-side
vias 21a.
[0119] FIG. 16 shows the planar layout of the n-side vias 22a and the p-side vias 21a; and
FIG. 17 is a plan view in which the n-side interconnect layer 32 and the p-side interconnect
layer 31 are overlaid onto FIG. 16.
[0120] The n-side vias 22a and the p-side vias 21a are provided to be divided into the left
and right with respect to the center in the first direction X. In FIGS. 16 and 17,
the n-side vias 22a are provided in the region on the left side of the center in the
first direction X; and the p-side vias 21a are provided in the region on the right
side of the center in the first direction X.
[0121] The n-side interconnect layer 32 spreads in a region on the left side of the center
in the first direction X in FIG. 17. The multiple n-side electrodes 17a are electrically
connected respectively by means of the n-side vias 22a to one common n-side interconnect
layer 32.
[0122] The p-side interconnect layer 31 spreads in a region on the right side of the center
in the first direction X in FIG. 17. The p-side electrode 16a that spreads over the
entire second surface other than the n-side regions 14b is electrically connected
by means of the multiple p-side vias 21a to one common p-side interconnect layer 31.
[0123] The n-side interconnect layer 32 and the p-side interconnect layer 31 spread to be
divided into the left and right with the same surface area with the center in the
first direction X interposed. The n-side interconnect layer 32 and the p-side interconnect
layer 31 are separated from each other on the insulating film 18.
[0124] As shown in FIGS. 12, 13, and 14, the p-type metal pillar 23 is provided on the p-side
interconnect layer 31. The p-side interconnect layer 31 and the p-type metal pillar
23 are included in the p-side interconnect unit of the embodiment. The n-side metal
pillar 24 is provided on the n-side interconnect layer 32. The n-side interconnect
layer 32 and the n-side metal pillar 24 are included in the n-side interconnect unit
of the embodiment.
[0125] The resin layer 25 is stacked on the insulating film 18. The resin layer 25 covers
the periphery of the n-side interconnect layer 32, the periphery of the n-side metal
pillar 24, the periphery of the p-side interconnect layer 31, and the periphery of
the p-type metal pillar 23. The resin layer 25 is filled between the p-side interconnect
layer 31 and the n-side interconnect layer 32 and between the p-type metal pillar
23 and the n-side metal pillar 24.
[0126] The side surface of the p-type metal pillar 23 and the side surface of the n-side
metal pillar 24 are covered with the resin layer 25. The surface of the p-type metal
pillar 23 on the side opposite to the p-side interconnect layer 31 is exposed from
the resin layer 25 and functions as the p-side external terminal 23a. The surface
of the n-side metal pillar 24 on the side opposite to the n-side interconnect layer
32 is exposed from the resin layer 25 and functions as the n-side external terminal
24a.
[0127] The p-side external terminal 23a and the n-side external terminal 24a are bonded
to pads formed in a not-shown mounting substrate via solder, etc.
[0128] The surface area of the p-side interconnect layer 31 contacting the p-side pad 16b
by means of the multiple p-side vias 21a is greater than the surface area of the n-side
interconnect layer 32 contacting the n-side pads 17b by means of the multiple n-side
vias 22a. Therefore, the current distribution to the light emitting layer 13 can be
improved; and the heat dissipation of the heat of the light emitting layer 13 can
be improved.
[0129] The surface area of the n-side interconnect layer 32 spreading on the insulating
film 18 is greater than the surface area where the n-side interconnect layer 32 connects
the n-side pads 17b by means of the n-side vias 22a.
[0130] According to the second embodiment, a high light output can be obtained by the light
emitting layer 13 spreading over a region that is larger than the n-side electrodes
17a. Also, the n-side electrodes 17a provided in the n-side regions 14b that are narrower
than the region including the light emitting layer 13 are drawn out to the side opposite
to the light extraction surface (the first surface 15a) as the n-side interconnect
layer 32 that has a larger surface area.
[0131] As shown in FIG. 13, the first semiconductor layer 11 is electrically connected to
the n-side external terminal 24a via the n-side electrodes 17a, the n-side pads 17b,
the n-side vias 22a, the n-side interconnect layer 32, and the n-side metal pillar
24.
[0132] As shown in FIG. 14, the second semiconductor layer 12 is electrically connected
to the p-side external terminal 23a via the p-side electrode 16a, the p-side pad 16b,
the p-side vias 21a, the p-side interconnect layer 31, and the p-type metal pillar
23.
[0133] The p-type metal pillar 23 is thicker than the p-side interconnect layer 21 and thicker
than the p-side interconnect layer 31. The n-side metal pillar 24 is thicker than
the n-side interconnect layers 22 and thicker than the n-side interconnect layer 32.
The thicknesses of the p-type metal pillar 23, the n-side metal pillar 24, and the
resin layers 25 are thicker than the semiconductor layer 15. The thicknesses of the
p-type metal pillar 23 and the n-side metal pillar 24 are thicker than the thickness
of the chip which includes the semiconductor layer 15, the p-side electrode 16a, the
p-side pad 16b, the n-side electrodes 17a, and the n-side pads 17b.
[0134] According to the second embodiment, the semiconductor layer 15 can be stably supported
by the support body including the p-type metal pillar 23, the n-side metal pillar
24, and the resin layer 25 even if the substrate used to form the semiconductor layer
15 is removed; and the mechanical strength of the semiconductor light emitting device
1 can be increased.
[0135] The stress applied to the semiconductor layer 15 via the solder in the state in which
the semiconductor light emitting device 2 is mounted to the mounting substrate via
the p-side external terminal 23a and the n-side external terminal 24a can be relaxed
by being absorbed by the p-type metal pillar 23 and the n-side metal pillar 24.
[0136] The substrate used when forming the semiconductor layer 15 is removed from the first
surface 15a. Therefore, the semiconductor light emitting device 2 can be thinner.
[0137] As shown in FIG. 20, the phosphor layer 50 can be provided on the first surface 15a.
The phosphor layer 50 includes the transparent resin 51 as a transparent medium and
the phosphor 52 having a multiple particle configuration dispersed in the transparent
resin 51.
[0138] The transparent resin 51 is transmissive to the light emitted by the light emitting
layer 13 and the light emitted by the phosphor 52 and may include, for example, a
silicone resin, an acrylic resin, a phenyl resin, etc.
[0139] The phosphor 52 is capable of absorbing the emitted light (the excitation light)
of the light emitting layer 13 and emitting a wavelength-converted light. Therefore,
the semiconductor light emitting device of the second embodiment is capable of emitting
a mixed light of the light emitted by the light emitting layer 13 and the wavelength-converted
light of the phosphor 52.
[0140] For example, white, lamp, etc., can be obtained as a mixed color of the blue light
of the light emitting layer 13 which is the InGaN-based material and the yellow light
which is the wavelength-converted light of the phosphor 52 in the case where the phosphor
52 is a yellow phosphor that emits yellow light. The phosphor layer 50 may have a
configuration including multiple types of phosphors (e.g., a red phosphor that emits
red light and a green phosphor that emits green light).
[0141] In the semiconductor light emitting device 2 of the second embodiment, the p-side
electrode 16a and the n-side electrodes 17a are provided on the second surface on
the side opposite to the first surface 15a which is the main extraction surface of
the light. Accordingly, the light extraction from the first surface 15a is not impeded
by the electrodes. The p-side electrode 16a is provided on the region including the
light emitting layer 13. The n-side electrodes 17a are provided on the first semiconductor
layer 11 not including the light emitting layer 13.
[0142] According to the second embodiment, the contact surface between the n-side electrodes
17a and the first semiconductor layer 11, i.e., the n-side regions 14b at the second
surface of the first semiconductor layer 11, have a uniform disposition in the second
surface. Therefore, a uniform current distribution in the surface direction of the
light emitting layer 13 can be realized while increasing the light emission surface
area by reducing the region not including the light emitting layer 13.
[0143] In the second embodiment as well, the p-side region 14a and the light emitting layer
13 exist completely around the n-side regions 14b and the n-side electrodes 17a. Accordingly,
the current spreads from one n-side electrode 17a to the entire peripheral region
of the one n-side electrode 17a; and the current can be supplied efficiently to the
entire region of the light emitting layer 13. Accordingly, according to the second
embodiment, the entire region of the light emitting layer 13 can be efficiently caused
to emit light.
[0144] Although the multiple n-side electrodes 17a are separated from each other on the
second surface of the first semiconductor layer 11, the multiple n-side electrodes
17a are connected on the side opposite to the light extraction surface (the first
surface 15a) to a common n-side interconnect unit by which the mounting to the mounting
substrate is performed. Therefore, the same potential can be provided to the multiple
n-side electrodes 17a by a simple configuration without performing wire bonding to
each of the multiple n-side electrodes 17a.
[0145] A method for manufacturing the semiconductor light emitting device 2 of the second
embodiment will now be described with reference to FIG. 15 to FIG. 19B.
[0146] FIG. 18A shows the C-C' cross section of FIG. 15; and FIG. 18B shows the D-D' cross
section of FIG. 15.
[0147] Similarly to the first embodiment, the semiconductor layer 15 is formed on the entire
surface of the substrate 10. Subsequently, a portion of the first semiconductor layer
11 is exposed by removing a portion of the light emitting layer 13 and the second
semiconductor layer 12 as shown in FIG. 18A by, for example, RIE using a not-shown
resist. The first semiconductor layer 11 is selectively exposed in a rectangular configuration.
[0148] The regions where the first semiconductor layer 11 is exposed are the n-side regions
14b which do not include the light emitting layer 13 and the second semiconductor
layer 12. The region where the second semiconductor layer 12 and the light emitting
layer 13 are left is the p-side region 14a.
[0149] The n-side electrodes 17a and the n-side pads 17b are formed on the n-side regions
14b. The p-side electrode 16a and the p-side pad 16b are formed on the front surface
of the second semiconductor layer 12 of the p-side region 14a.
[0150] For example, a silicon nitride film and/or a silicon oxide film may be formed by
CVD as a passivation film between the p-side pad 16b and the n-side pads 17b and/or
on the end surface (the side surface) of the light emitting layer 13.
[0151] Then, after all of the exposed portions on the major surface of the substrate 10
are covered with the insulating film 18 shown in FIGS. 19A and 19B, the first openings
18a and the second openings 18b are made selectively in the insulating film 18 by
patterning the insulating film 18 by etching. FIGS. 19A and 19B correspond to cross
sections of FIGS. 18A and 18B, respectively.
[0152] As shown in FIG. 19B, the first openings 18a are multiply formed; and each of the
first openings 18a reaches the p-side pad 16b. As shown in FIG. 19A, the second openings
18b are made respectively on the multiple n-side pads 17b; and the second openings
18b respectively reach the n-side pads 17b.
[0153] Then, Cu electroplating is performed using a not-shown metal film as a seed metal
(a current path) after forming the metal film on the front surface of the insulating
film 18, the inner walls (the side walls and the bottom portions) of the first openings
18a, and the inner walls (the side walls and the bottom portions) of the second openings
18b.
[0154] Thereby, as shown in FIGS. 13, 14, 16, and 17, the p-side vias 21a are formed inside
the first openings 18a; the n-side vias 22a are formed inside the second openings
18b; and the p-side interconnect layer 31 and the n-side interconnect layer 32 are
formed on the insulating film 18. The p-side vias 21a, the n-side vias 22a, the p-side
interconnect layer 31, and the n-side interconnect layer 32 are made of, for example,
a copper material formed simultaneously by plating using a not-shown plating resist.
[0155] Cu electroplating also is used to form the p-type metal pillar 23 on the p-side interconnect
layer 31 and to form the n-side metal pillar 24 on the n-side interconnect layer 32.
[0156] After forming the p-type metal pillar 23 and the n-side metal pillar 24, the resin
layer 25 is stacked on the insulating film 41. The resin layer 25 covers the p-side
interconnect layer 31, the n-side interconnect layer 32, the p-type metal pillar 23,
and the n-side metal pillar 24.
[0157] Then, the substrate 10 described above that is used to form the semiconductor layer
15 is removed. In the case where the substrate 10 is the sapphire substrate, the substrate
10 can be removed by, for example, laser lift-off. In the case where the substrate
10 is the silicon substrate, the substrate 10 can be removed by etching.
[0158] Because the stacked body described above formed on the major surface of the substrate
10 is reinforced by the p-type metal pillar 23, the n-side metal pillar 24, and the
resin layer 25 that are thicker than the semiconductor layer 15, it is possible to
maintain the wafer state even in the case where there is no substrate 10.
[0159] The resin layer 25 and the metals included in the p-type metal pillar 23 and the
n-side metal pillar 24 are materials more flexible than the semiconductor layer 15.
The semiconductor layer 15 is supported by such a flexible support body. Therefore,
destruction of the semiconductor layer 15 can be avoided even in the case where the
large internal stress generated in the epitaxial growth of the semiconductor layer
15 on the substrate 10 is relieved all at once when peeling the substrate 10.
[0160] The first surface 15a of the semiconductor layer 15, from which the substrate 10
is removed, is cleaned. Subsequently, wet etching of the first surface 15a is performed
using, for example, a KOH (potassium hydroxide) aqueous solution, TMAH (tetramethylammonium
hydroxide), etc. Thereby, an unevenness is formed in the first surface 15a due to
the difference of the etching rates that depend on the crystal plane orientation.
Or, the unevenness may be formed in the first surface 15a by performing etching after
the patterning using the resist. The light extraction efficiency can be increased
by the unevenness being formed in the first surface 15a.
[0161] If necessary, the phosphor layer 50 shown in FIG. 20 is formed on the first surface
15a. The liquid transparent resin 51 into which the phosphor 52 is dispersed is thermally
cured after being supplied onto the first surface 15a by a method such as, for example,
printing, potting, molding, compression molding, etc.
[0162] Subsequently, singulation into the multiple semiconductor light emitting devices
2 is performed by cutting the stacked body recited above. For example, cutting is
performed using a dicing blade. Or, the cutting may be performed using laser irradiation.
[0163] The semiconductor light emitting device 1 that is singulated may have a single-chip
structure including one semiconductor layer 15 or may have a multi-chip structure
including multiple semiconductor layers 15.
[0164] Because each of the processes described above until the dicing is performed can be
performed collectively in the wafer state, it is unnecessary to perform the interconnects
and the packaging for every singulated individual device; and it becomes possible
to drastically reduce the production costs. In other words, the interconnects and
the packaging are already complete in the singulated state. Therefore, the productivity
can be increased; and as a result, price reductions become easy.
[0165] In the embodiment described above, the p-side interconnect layer 31 and the n-side
interconnect layer 32 may be bonded to the pads of the mounting substrate without
providing the p-type metal pillar 23 and the n-side metal pillar 24.
[0166] The p-side interconnect layer 31 and the p-type metal pillar 23 are not limited to
being separate entities; and the p-side interconnect layer 31 and the p-type metal
pillar 23 may be provided as a single body by the same process. Similarly, the n-side
interconnect layer 32 and the n-side metal pillar 24 are not limited to being separate
entities; and the n-side interconnect layer 32 and the n-side metal pillar 24 may
be provided as a single body by the same process.
Third embodiment
[0167] FIG. 32A is a schematic plan view of a semiconductor light emitting device 3 of a
third embodiment; and FIG. 32B is a schematic cross-sectional view of the semiconductor
light emitting device 3 of the third embodiment.
[0168] FIG. 32A shows, for example, four semiconductor light emitting devices 3 singulated
from the wafer state. FIG. 32B is the E-E' cross-sectional view of FIG. 32A.
[0169] Similarly to the first and second embodiments recited above, the semiconductor light
emitting device 3 of the third embodiment includes the semiconductor layer 15. The
semiconductor layer 15 includes the first semiconductor layer 11, the second semiconductor
layer 12, and the light emitting layer 13.
[0170] The first semiconductor layer 11 has the first surface 15a and the second surface
provided on the side opposite to the first surface 15a. As shown in FIG. 32B, the
second surface has a p-side region 80a and n-side regions 80b. The first semiconductor
layer 11 includes, for example, a foundation buffer layer and an n-type GaN layer.
[0171] The light emitting layer (the active layer) 13 is provided on the p-side region 80a
at the second surface of the first semiconductor layer 11. The light emitting layer
13 has, for example, an InGaN multiple quantum well structure in which multiple pairs
of an InGaN well layer and a GaN or InGaN barrier layer are stacked and emits blue
light, violet light, bluish-violet light, ultraviolet light, etc.
[0172] The second semiconductor layer 12 including a p-type GaN layer is provided on the
light emitting layer 13. The light emitting layer 13 is provided between the first
semiconductor layer 11 and the second semiconductor layer 12. The light emitting layer
13 and the second semiconductor layer 12 are not provided in the n-side regions 80b
at the second surface of the first semiconductor layer 11.
[0173] The first surface 15a of the first semiconductor layer 11 functions as the main extraction
surface of the light; and the light emitted by the light emitting layer 13 is emitted
outside the semiconductor layer 15 mainly from the first surface 15a. A p-side electrode
62, n-side electrodes 61, and an n-side reflecting electrode 63 described below are
provided on the side opposite to the first surface 15a.
[0174] The p-side electrode 62 is provided on the front surface of the second semiconductor
layer 12. The n-side electrodes 61 are provided on the n-side regions 80b at the second
surface of the first semiconductor layer 11.
[0175] As shown in FIGS. 22A and 22B, the n-side regions 80b are formed by the front surface
of the first semiconductor layer 11 being exposed by selectively removing a portion
of the light emitting layer 13 and the second semiconductor layer 12 formed on the
entire surface of the second surface of the first semiconductor layer 11.
[0176] The n-side regions 80b are formed in multiple locations (e.g., two locations) for
every one chip. The n-side electrodes 61 are provided respectively on the n-side regions
80b. The two n-side electrodes 61 are positioned with the second semiconductor layer
12 interposed in the surface direction of the second surface.
[0177] An insulating film 71 is provided on the second semiconductor layer 12 provided between
the two n-side electrodes 61; and the p-side electrode 62 is not provided on the second
semiconductor layer 12 provided between the two n-side electrodes 61. The n-side reflecting
electrode 63 is provided on the two n-side electrodes 61 and on the insulating film
71 on the second semiconductor layer 12 interposed between the n-side electrodes 61.
[0178] In other words, the n-side reflecting electrode 63 includes two n-side vias 63a provided
respectively on the two n-side electrodes 61, and a linking portion 63b linking the
two n-side vias 63a; and the n-side vias 63a and the linking portion 63b are provided
as a single body from the same material. The linking portion 63b extends in a direction
linking the two n-side vias 63a and is provided on the second semiconductor layer
12 interposed between the two n-side electrodes 61 with the insulating film 71 interposed
between the linking portion 63b and the second semiconductor layer 12.
[0179] The n-side reflecting electrode 63 is provided to straddle the second semiconductor
layer 12 provided between the two n-side electrodes 61; and the planar configuration
of the n-side reflecting electrode 63 is formed in a rectangular configuration as
shown in FIG. 25A.
[0180] The direction in which the n-side reflecting electrode 63 extends is taken as the
first direction X; and a direction orthogonal to the first direction X in the plan
view of FIG. 25A is taken as the second direction Y. The light emitting layer 13,
the second semiconductor layer 12, and the p-side electrode 62 are provided on both
second direction Y sides of the n-side reflecting electrode 63. The n-side reflecting
electrode 63 is provided between the p-side electrode 62 in the second direction Y.
[0181] The p-side electrode 62, the n-side electrodes 61, and the n-side reflecting electrode
63 are provided on the same surface side which is the side opposite to the first surface
15a which is the main light extraction surface of the semiconductor layer 15. The
p-side electrode 62 is provided on the region including the light emitting layer 13;
and the n-side electrodes 61 are provided on the n-side regions 80b not including
the light emitting layer 13. The n-side reflecting electrode 63 is provided on the
n-side electrodes 61 and on the light emitting layer 13 between the n-side electrodes
61.
[0182] The p-side electrode 62 contacts the second semiconductor layer 12 and includes,
for example, a contact layer including at least one selected from nickel (Ni), gold
(Au), and rhodium (Rh) that is capable of forming an alloy with the gallium (Ga) included
in the second semiconductor layer 12. The p-side electrode 62 further includes a reflective
layer that is provided on the contact layer, has a reflectance for the light emitted
by the light emitting layer 13 that is higher than that of the contact layer, and
includes, for example, silver (Ag) as the main component.
[0183] The n-side electrodes 61 contact the first semiconductor layer 11 and include, for
example, at least one selected from nickel (Ni), gold (Au), and rhodium (Rh) that
is capable of forming an alloy with the gallium (Ga) included in the first semiconductor
layer 11.
[0184] The n-side reflecting electrode 63 is formed simultaneously with the p-side electrode
62 from the same material. The n-side reflecting electrode 63 has a reflectance for
the light emitted by the light emitting layer 13 that is higher than that of the n-side
electrodes 61 and includes, for example, silver (Ag) as the main component.
[0185] An insulating film 76 is provided on the insulating film 71, on the p-side electrode
62, and on the n-side reflecting electrode 63. The insulating film 76 covers the p-side
electrode 62 and the n-side reflecting electrode 63.
[0186] The insulating film 76 is, for example, a resin such as polyimide, etc. Or, an inorganic
film such as a silicon oxide film, a silicon nitride film, etc., may be used as the
insulating film 76.
[0187] A p-side interconnect layer 65 and an n-side interconnect layer 66 are provided to
be separated from each other on the insulating film 76. The p-side interconnect layer
65 and the n-side interconnect layer 66 are formed by electroplating as described
below. The p-side interconnect layer 65 also includes a metal film 64 used as the
seed metal in the plating. Similarly, the n-side interconnect layer 66 also includes
the metal film 64 used as the seed metal.
[0188] The p-side interconnect layer 65 is provided on the p-side electrode 62 with the
insulating film 76 interposed. A first opening is made in the insulating film 76 to
reach the p-side electrode 62; and the p-side interconnect layer 65 is electrically
connected to the p-side electrode 62 by means of a p-side via provided inside the
first opening.
[0189] The n-side interconnect layer 66 is provided on the n-side reflecting electrode 63
with the insulating film 76 interposed. The second opening is made in the insulating
film 76 to reach the n-side reflecting electrode 63; and the n-side interconnect layer
66 is electrically connected to the n-side reflecting electrode 63 and the n-side
electrodes 61 by means of an n-side via provided inside the second opening.
[0190] A p-type metal pillar 67 is provided on the p-side interconnect layer 65. The p-side
interconnect layer 65 and the p-type metal pillar 67 are included in the p-side interconnect
unit of the embodiment. An n-side metal pillar 68 is provided on the n-side interconnect
layer 66. The n-side interconnect layer 66 and the n-side metal pillar 68 are included
in the n-side interconnect unit of the embodiment.
[0191] A resin layer 77 is stacked on the insulating film 76 as another insulating film.
The resin layer 77 covers the periphery of the p-side interconnect unit and the periphery
of the n-side interconnect unit. Also, the resin layer 77 is filled between the p-type
metal pillar 67 and the n-side metal pillar 68.
[0192] The side surface of the p-type metal pillar 67 and the side surface of the n-side
metal pillar 68 are covered with the resin layer 77. The surface of the p-type metal
pillar 67 on the side opposite to the p-side interconnect layer 65 is exposed from
the resin layer 77 and functions as a p-side external terminal 67a. The surface of
the n-side metal pillar 68 on the side opposite to the n-side interconnect layer 66
is exposed from the resin layer 77 and functions as an n-side external terminal 68a.
The p-side external terminal 67a and the n-side external terminal 68a are bonded to
pads formed in a not-shown mounting substrate via solder, etc.
[0193] The distance between the p-side external terminal 67a and the n-side external terminal
68a exposed at the same surface (in FIG. 32B, the upper surface) of the resin layer
77 is greater than the distance between the p-side interconnect layer 65 and the n-side
interconnect layer 66 on the insulating film 76. The p-side external terminal 67a
and the n-side external terminal 68a are separated by a distance such that the p-side
external terminal 67a and the n-side external terminal 68a are not shorted to each
other by the solder, etc., when mounting to the mounting substrate.
[0194] The p-side interconnect layer 65 and the n-side interconnect layer 66 can be near
the process limits; and the surface area of the p-side interconnect layer 65 and the
n-side interconnect layer 66 can be increased. As a result, the current distribution
and the heat dissipation can be improved.
[0195] The surface area of the n-side interconnect layer 66 spreading on the insulating
film 76 is greater than the total surface area of the multiple n-side electrodes 61
on the second surface.
[0196] According to the third embodiment, a high light output can be obtained by the light
emitting layer 13 formed over the region that is larger than the n-side electrodes
61. Further, the n-side electrodes 61 provided in the region that is narrower than
the region including the light emitting layer 13 is drawn out to the mounting surface
side as the n-side interconnect layer 66 that has a larger surface area.
[0197] The p-type metal pillar 67 is thicker than the p-side interconnect layer 65; and
the n-side metal pillar 68 is thicker than the n-side interconnect layer 66. The thicknesses
of the p-type metal pillar 67, the n-side metal pillar 68, and the resin layers 77
are thicker than the semiconductor layer 15. Here, "thickness" is the thickness in
the vertical direction in FIG. 32B.
[0198] The thicknesses of the p-type metal pillar 67 and the n-side metal pillar 68 are
thicker than the thickness of the stacked body (the chip) including the semiconductor
layer 15, the p-side electrode 62, the n-side electrodes 61, and the n-side reflecting
electrode 63. The aspect ratios (the ratios of the thickness to the planar size) of
the metal pillars 67 and 68 are not limited to being 1 or more and may be smaller
than 1. In other words, the thicknesses of the metal pillars 67 and 68 may be less
than the planar sizes of the metal pillars 67 and 68.
[0199] According to the third embodiment, the semiconductor layer 15 can be stably supported
by the support body including the p-type metal pillar 67, the n-side metal pillar
68, and the resin layer 77 even if the substrate 10 described below used to form the
semiconductor layer 15 is removed; and the mechanical strength of the semiconductor
light emitting device 3 can be increased.
[0200] Copper, gold, nickel, silver, etc., may be used as the materials of the p-side interconnect
layer 65, the n-side interconnect layer 66, the p-type metal pillar 67, and the n-side
metal pillar 68. Among these, good thermal conductivity, high migration resistance,
and excellent adhesion with insulating materials are obtained when copper is used.
[0201] The resin layer 77 reinforces the p-type metal pillar 67 and the n-side metal pillar
68. It is desirable for the resin layer 77 to have a coefficient of thermal expansion
near to or the same as that of the mounting substrate. Examples of such a resin layer
25 include, for example, an epoxy resin, a silicone resin, a fluorocarbon resin, etc.
[0202] The stress applied to the semiconductor layer 15 via the solder in the state in which
the semiconductor light emitting device 3 is mounted to the mounting substrate via
the p-side external terminal 67a and the n-side external terminal 68a can be relaxed
by being absorbed by the p-type metal pillar 67 and the n-side metal pillar 68.
[0203] As described below, the substrate 10 used when forming the semiconductor layer 15
is removed from the first surface 15a. Therefore, the semiconductor light emitting
device 3 can be thinner.
[0204] The phosphor layer 50 is provided on the first surface 15a. The phosphor layer 50
includes the transparent resin 51 as a transparent medium and the phosphor 52 having
a multiple particle configuration dispersed in the transparent resin 51.
[0205] The transparent resin 51 is transmissive to the light emitted by the light emitting
layer 13 and the light emitted by the phosphor 52 and may include, for example, a
silicone resin, an acrylic resin, a phenyl resin, etc.
[0206] The phosphor 52 is capable of absorbing the emitted light (the excitation light)
of the light emitting layer 13 and emitting a wavelength-converted light. Therefore,
the semiconductor light emitting device 3 of the third embodiment is capable of emitting
a mixed light of the light emitted by the light emitting layer 13 and the wavelength-converted
light of the phosphor 52.
[0207] For example, white, lamp, etc., can be obtained as a mixed color of the blue light
of the light emitting layer 13 which is the InGaN-based material and the yellow light
which is the wavelength-converted light of the phosphor 52 in the case where the phosphor
52 is a yellow phosphor that emits yellow light. The phosphor layer 50 may have a
configuration including multiple types of phosphors (e.g., a red phosphor that emits
red light and a green phosphor that emits green light).
[0208] In the semiconductor light emitting device 3 of the third embodiment, the p-side
electrode 62, the n-side electrodes 61, and the n-side reflecting electrode 63 are
provided at the second surface on the side opposite to the first surface 15a which
is the main extraction surface of the light. Accordingly, the light extraction from
the first surface 15a is not impeded by the electrodes.
[0209] The n-side regions 80b at the second surface of the first semiconductor layer 11
and the n-side electrodes 61 provided on the n-side regions 80b are interspersed at
the second surface in a dot configuration or an island configuration. Therefore, the
uniform current distribution in the surface direction of the light emitting layer
13 can be realized while increasing the light emission surface area by reducing the
region not including the light emitting layer 13.
[0210] As shown in FIG. 25A, the p-side electrode 62 and the n-side reflecting electrode
63 that are highly reflective to the light emitted by the light emitting layer 13
spread over substantially the entire surface on the side opposite to the light extraction
surface (the first surface 15a). Accordingly, the reflecting surface area of the light
radiated from the light emitting layer 13 to the side opposite to the light extraction
surface (the first surface 15a) can be large; and a high light extraction efficiency
is obtained.
[0211] The n-side electrodes 61 are separated into a plurality on the second surface of
the first semiconductor layer 11. The multiple n-side electrodes 61 are electrically
connected to each other by the n-side reflecting electrode 63 provided on the second
semiconductor layer 12 existing between the multiple n-side electrodes 61 with the
insulating film 71 interposed between the n-side reflecting electrode 63 and the second
semiconductor layer 12.
[0212] The reflecting surface area of the side opposite to the light extraction surface
can be increased by using, for example, a material including silver that has a high
reflectance as the electrode to connect the multiple n-side electrodes 61. By forming
the n-side reflecting electrode 63 from the same material as the p-side electrode
62 when forming the p-side electrode 62, the processes do not increase and costs can
be lower.
[0213] A method for manufacturing the semiconductor light emitting device 3 of the third
embodiment will now be described with reference to FIG. 21A to FIG. 32B. FIG. 21A
to FIG. 32B show a partial region in the wafer state.
[0214] FIG. 21B, FIG. 22B, FIG. 23B, FIG. 24B, FIG. 25B, FIG. 26B, FIG. 27B, FIG. 28B, FIG.
29B, FIG. 30B, and FIG. 32B show the E-E' cross sections of FIG. 21A, FIG. 22A, FIG.
23A, FIG. 24A, FIG. 25A, FIG. 26A, FIG. 27A, FIG. 28A, FIG. 29A, FIG. 30A, and FIG.
32A, respectively.
[0215] As shown in FIG. 21B, the semiconductor layer 15 is formed on the substrate 10. First,
the first semiconductor layer 11 is formed on the major surface of the substrate 10;
the light emitting layer 13 is formed on the first semiconductor layer 11; and the
second semiconductor layer 12 is formed on the light emitting layer 13.
[0216] Crystal growth of the semiconductor layer 15 which is a nitride semiconductor of
In
xAl
yGa
1-x-yN (0≤
x≤1, 0≤
y≤1, and
x+
y≤1) may be performed by, for example, MOCVD on a sapphire substrate. Or, a silicon
substrate may be used as the substrate 10.
[0217] The semiconductor layer 15 is formed on the entire surface of the substrate 10. Subsequently,
a portion of the first semiconductor layer 11 is exposed by removing a portion of
the light emitting layer 13 and the second semiconductor layer 12 as shown in FIGS.
22A and 22B by, for example, RIE using a not-shown resist. The semiconductor layer
15 is separated into a plurality on the substrate 10 by a trench 73 made in a planar
pattern having, for example, a lattice configuration.
[0218] The regions where the first semiconductor layer 11 is exposed are the n-side regions
80b not including the light emitting layer 13 and the second semiconductor layer 12.
[0219] Then, after covering all of the exposed portions on the substrate 10 with the insulating
film 71 shown in FIGS. 23A and 23B, openings 74 are made selectively in the insulating
film 71. The insulating film 71 is a resin film or an inorganic film such as a silicon
nitride film, a silicon oxide film, etc.
[0220] The openings 74 are made on the portion (the n-side regions 80b) where the first
semiconductor layer 11 is exposed to reach the front surface of the n-side regions
80b. The n-side electrodes 61 are formed inside the openings 74.
[0221] Then, an opening 75 is made in the insulating film 71 on the second semiconductor
layer 12 by removing a portion of the insulating film 71 covering the front surface
of the second semiconductor layer 12 as shown in FIGS. 24A and 24B. The opening 75
is not made on the second semiconductor layer 12 provided between the n-side electrodes
61 in the X direction; and the front surface of the second semiconductor layer 12
between the n-side electrodes 61 remains covered with the insulating film 71.
[0222] As shown in FIGS. 25A and 25B, the n-side vias 63a are formed on the n-side electrodes
61 inside the openings 74; the linking portion 63b is formed on the insulating film
71 on the second semiconductor layer 12 between the n-side electrodes 61; and the
p-side electrode 62 is formed on the front surface of the second semiconductor layer
12 inside the opening 75. In other words, the p-side electrode 62 and the n-side reflecting
electrode 63 are formed simultaneously from the same material. The p-side electrode
62 and the n-side reflecting electrode 63 may be formed by, for example, sputtering
using a not-shown mask.
[0223] Then, after covering all of the exposed portions on the substrate 10 major surface
with the insulating film 76 shown in FIG. 26B, a first opening 76a is made by removing
a portion of the insulating film 76 on the p-side electrode 62; and a second opening
76b is made by removing a portion of the insulating film 76 on the n-side reflecting
electrode 63. The p-side electrode 62 is exposed in the first opening 76a; and the
n-side reflecting electrode 63 is exposed in the second opening 76b.
[0224] Then, as shown in FIG. 27B, the metal film 64 is formed on the front surface of the
insulating film 76, the inner wall (the side wall and the bottom portion) of the first
opening 76a, and the inner wall (the side wall and the bottom portion) of the second
opening 76b. The metal film 64 is used as the seed metal of the plating described
below.
[0225] The metal film 64 is formed by, for example, sputtering. The metal film 64 includes,
for example, a stacked film of titanium (Ti) and copper (Cu) stacked in order from
the lower layer side. Or, an aluminum film may be used instead of the titanium film.
[0226] Then, a resist 81 is formed selectively on the metal film 64; and Cu electroplating
is performed using the metal film 64 as a current path.
[0227] Thereby, the p-side interconnect layer 65 and the n-side interconnect layer 66 are
formed selectively on the metal film 64. The p-side interconnect layer 65 and the
n-side interconnect layer 66 are made of, for example, a copper material formed simultaneously
by plating.
[0228] Then, as shown in FIGS. 28A and 28B, a resist 82 for forming the metal pillars is
formed. The resist 82 is thicker than the resist 81 described above. The resist 81
may be left without being removed in the previous process; and the resist 82 may be
formed to overlap the resist 81.
[0229] Continuing, Cu electroplating using the metal film 64 as a current path is performed
using the resist 82 as a mask. Thereby, the p-type metal pillar 67 is formed on the
p-side interconnect layer 65; and the n-side metal pillar 68 is formed on the n-side
interconnect layer 66. The p-type metal pillar 67 and the n-side metal pillar 68 are
made of, for example, a copper material formed simultaneously by plating.
[0230] The resist 82 is removed as shown in FIG. 29B using, for example, a solvent or oxygen
plasma. Subsequently, the exposed portion of the metal film 64 used as the seed metal
is removed by wet etching. Thereby, as shown in FIG. 29B, the electrical connection
by means of the metal film 64 between the p-side interconnect layer 65 and the n-side
interconnect layer 66 is broken.
[0231] Then, after forming the resin layer 77 to cover the p-side interconnect layer 65,
the n-side interconnect layer 66, the p-type metal pillar 67, and the n-side metal
pillar 68 as shown in FIGS. 30A and 30B, the resin layer 77 is polished to expose
the end surface (the p-side external terminal 67a) of the p-type metal pillar 67 and
the end surface (the n-side external terminal 68a) of the n-side metal pillar 68 from
the resin layer 77.
[0232] The resin layer 77 is insulative. The resin layer 77 may be light-shielding to the
light emitted by the light emitting layer 13 by the resin layer 77 containing, for
example, carbon black.
[0233] Then, the substrate 10 is removed as shown in FIG. 31A. In the case where the substrate
10 is the sapphire substrate, the substrate 10 can be removed by, for example, laser
lift-off. Specifically, laser light is irradiated from the back surface side of the
substrate 10 toward the first semiconductor layer 11. The substrate 10 is transmissive
to the laser light; and the laser light has a wavelength in the absorption region
of the first semiconductor layer 11.
[0234] When the laser light reaches the interface between the substrate 10 and the first
semiconductor layer 11, the first semiconductor layer 11 proximal to the interface
decomposes by absorbing the energy of the laser light. The first semiconductor layer
11 decomposes into gallium (Ga) and nitrogen gas. A micro gap is made between the
substrate 10 and the first semiconductor layer 11 by this decomposition reaction;
and the substrate 10 and the first semiconductor layer 11 separate.
[0235] The irradiation of the laser light is performed over the entire wafer by performing
multiply for every set region; and the substrate 10 is removed.
[0236] In the case where the substrate 10 is the silicon substrate, the substrate 10 can
be removed by etching.
[0237] Because the stacked body described above formed on the major surface of the substrate
10 is reinforced by the p-type metal pillar 67, the n-side metal pillar 68, and the
resin layer 77 that are thicker than the semiconductor layer 15, it is possible to
maintain the wafer state even in the case where there is no substrate 10.
[0238] The resin layer 77 and the metals included in the p-type metal pillar 67 and the
n-side metal pillar 68 are materials more flexible than the semiconductor layer 15.
The semiconductor layer 15 is supported by such a flexible support body. Therefore,
destruction of the semiconductor layer 15 can be avoided even in the case where the
large internal stress generated in the epitaxial growth of the semiconductor layer
15 on the substrate 10 is relieved all at once when peeling the substrate 10.
[0239] As shown in FIG. 31B, the phosphor layer 50 is formed on the first surface 15a exposed
by the removal of the substrate 10. The polishing process of the resin layer 77 described
above may be performed after the removal process of the substrate 10 or after the
formation of the phosphor layer 50.
[0240] The phosphor layer 50 is formed by thermally curing the liquid transparent resin
51 into which the phosphor 52 is dispersed after supplying the transparent resin 51
onto the first surface 15a by a method such as, for example, printing, potting, molding,
compression molding, etc.
[0241] Then, singulation into the multiple semiconductor light emitting devices 3 is performed
as shown in FIGS. 32A and 32B by cutting the resin layer 77, the insulating film 76,
the insulating film 71, the first semiconductor layer 11, and the phosphor layer 50
at the position of the trench 73 shown in FIG. 22A described above.
[0242] The singulated semiconductor light emitting device 3 may have a single-chip structure
including one semiconductor layer 15 or may have a multi-chip structure including
multiple semiconductor layers 15.
[0243] Because the processes described above until the dicing are performed collectively
in the wafer state, it is unnecessary to perform the interconnects and the packaging
for each of the individual devices that is singulated; and it becomes possible to
drastically reduce the production costs. In other words, the interconnects and the
packaging are already complete in the singulated state. Therefore, the productivity
can be increased; and as a result, price reductions become easy.
Fourth embodiment
[0244] FIG. 34A is a schematic plan view of a semiconductor light emitting device 4 of a
fourth embodiment. FIG. 34B is a schematic cross-sectional view of the semiconductor
light emitting device 4 of the fourth embodiment.
[0245] FIG. 34A shows, for example, four semiconductor light emitting devices 4 singulated
from the wafer state. FIG. 34B is the E-E' cross-sectional view of FIG. 34A.
[0246] The semiconductor light emitting device 4 of the fourth embodiment differs from the
semiconductor light emitting device 3 of the third embodiment in that the semiconductor
light emitting device 4 does not include the metal pillars 67 and 68 and the resin
layer 77.
[0247] In the semiconductor light emitting device 4 of the fourth embodiment, the substrate
10 used in the growth of the semiconductor layer 15 is left on the first surface 15a;
and the substrate 10 functions as a support body of the semiconductor layer 15. The
substrate 10 is, for example, a sapphire substrate that is transmissive to the light
emitted by the light emitting layer 13.
[0248] The refractive indexes of the GaN layer, the sapphire substrate, and air are 2.4,
1.8, and 1.0, respectively; and the refractive indexes of the media change in stages
in the direction in which the light is extracted. Therefore, the light extraction
efficiency can be increased. The phosphor layer 50 may be provided on the substrate
10.
[0249] Solder 91 is provided on the p-side interconnect layer 65; solder 92 is provided
on the n-side interconnect layer 66; and the semiconductor light emitting device 4
is mounted on the mounting substrate by bonding the solder 91 and 92 to the pads of
the mounting substrate.
[0250] The processes up to those shown in FIGS. 27A and 27B progress similarly to the third
embodiment recited above. Subsequently, as shown in FIGS. 33A and 33B, the solder
91 is formed on the p-side interconnect layer 65 and the solder 92 is formed on the
n-side interconnect layer 66 by plating using the resist 81 as a mask.
[0251] Subsequently, the resist 81 is removed; and the exposed portion of the metal film
64 used as the seed metal of the plating is removed as shown in FIG. 34B. Thereby,
the electrical connection by means of the metal film 64 between the p-side interconnect
layer 65 and the n-side interconnect layer 66 is broken.
[0252] Subsequently, singulation into the multiple semiconductor light emitting devices
4 is performed by cutting the insulating film 76, the insulating film 71, the first
semiconductor layer 11, and the substrate 10.
Fifth embodiment
[0253] FIG. 47A is a schematic plan view of a semiconductor light emitting device 5 of a
fifth embodiment; and FIG. 47B is a schematic cross-sectional view of the semiconductor
light emitting device 5 of the fifth embodiment.
[0254] FIG. 47A shows, for example, four semiconductor light emitting devices 5 singulated
from the wafer state. FIG. 47B is the E-E' cross-sectional view of FIG. 47A.
[0255] In addition to each of the components of the semiconductor light emitting device
3 of the third embodiment described above, the semiconductor light emitting device
5 of the fifth embodiment includes a transparent electrode 95. The transparent electrode
95 is transmissive (is transparent) to the light emitted by the light emitting layer
13; and the material of the transparent electrode 95 is, for example, ITO (Indium
Tin Oxide).
[0256] The transparent electrode 95 is provided on the second semiconductor layer 12 and
is not provided in the n-side regions 80b. The transparent electrode 95 is provided
between the p-side electrode 62 and the second semiconductor layer 12 and is electrically
connected to the p-side electrode 62 and the second semiconductor layer 12.
[0257] The transparent electrode 95 is provided also on the second semiconductor layer 12
under the n-side reflecting electrode 63. The insulating film 71 is provided between
the n-side reflecting electrode 63 and the transparent electrode 95; and the n-side
reflecting electrode 63 and the transparent electrode 95 do not connect to each other.
[0258] As shown in FIG. 37A which shows the top view of the transparent electrode 95, the
transparent electrode 95 is provided on the second semiconductor layer 12 in the same
planar pattern as the second semiconductor layer 12.
[0259] The transparent electrode 95 under the p-side electrode 62 and the transparent electrode
95 under the n-side reflecting electrode 63 are linked as a single body. Accordingly,
the current from the p-side electrode 62 can be supplied to the light emitting layer
13 under the n-side reflecting electrode 63 by means of the transparent electrode
95.
[0260] The second semiconductor layer 12 including the p-type GaN which has a high resistance
compared to an n-type GaN has an ability to cause the current to flow in the lateral
direction (the direction perpendicular to the thickness direction) that is inferior
to that of the first semiconductor layer 11 including the n-type GaN.
[0261] However, according to the fifth embodiment, the ability of the current supplied from
the second semiconductor layer 12 side to the light emitting layer 13 to flow in the
lateral direction can be increased by providing the transparent electrode 95 on the
second semiconductor layer 12. As a result, in particular, the light emission intensity
in the region under the n-side reflecting electrode 63 where the p-side electrode
62 is not provided can be increased.
[0262] By controlling the thickness of the transparent electrode 95 such that the distance
between the light emitting layer 13 and the n-side reflecting electrode 63 is 1/2
of the light emission wavelength of the light emitting layer 13, the reflection loss
due to interference can be suppressed; and a high reflection efficiency is obtained.
[0263] A method for manufacturing the semiconductor light emitting device 5 of the fifth
embodiment will now be described with reference to FIG. 36A to FIG. 47B. FIG. 36A
to FIG. 47B show a partial region in the wafer state.
[0264] FIG. 36B, FIG. 37B, FIG. 38B, FIG. 39B, FIG. 40B, FIG. 41B, FIG. 42B, FIG. 43B, FIG.
44B, FIG. 45B, and FIG. 47B show the E-E' cross sections of FIG. 36A, FIG. 37A, FIG.
38A, FIG. 39A, FIG. 40A, FIG. 41A, FIG. 42A, FIG. 43A, FIG. 44A, FIG. 45A, and FIG.
47A, respectively.
[0265] As shown in FIG. 36B, the transparent electrode 95 is formed on the entire surface
of the second semiconductor layer 12 after the semiconductor layer 15 including the
first semiconductor layer 11, the light emitting layer 13, and the second semiconductor
layer 12 is formed on the substrate 10.
[0266] Then, a portion of the first semiconductor layer 11 is exposed by removing a portion
of the stacked film of the transparent electrode 95, the second semiconductor layer
12, and the light emitting layer 13 as shown in FIGS. 37A and 37B by, for example,
RIE using a not-shown resist. The regions where the first semiconductor layer 11 is
exposed are the n-side regions 80b not including the transparent electrode 95, the
second semiconductor layer 12, and the light emitting layer 13.
[0267] Continuing, after covering all of the exposed portions on the substrate 10 with the
insulating film 71 shown in FIGS. 38A and 38B, the openings 74 are made selectively
in the insulating film 71. The opening 75 is made in the insulating film 71 on the
transparent electrode 95 by removing a portion of the insulating film 71 covering
the front surface of the transparent electrode 95 as shown in FIGS. 39A and 39B.
[0268] As shown in FIGS. 40A and 40B, the n-side vias 63a are formed on the n-side electrodes
61 inside the openings 74; the linking portion 63b is formed on the insulating film
71 on the second semiconductor layer 12 between the n-side electrodes 61; and the
p-side electrode 62 is formed on the front surface of the transparent electrode 95
inside the opening 75.
[0269] Then, after covering all of the exposed portions on the substrate 10 major surface
with the insulating film 76 shown in FIG. 41B, the first opening 76a is made by removing
a portion of the insulating film 76 on the p-side electrode 62; and the second opening
76b is made by removing a portion of the insulating film 76 on the n-side reflecting
electrode 63. The p-side electrode 62 in the first opening 76a is exposed; and the
n-side reflecting electrode 63 in the second opening 76b is exposed.
[0270] Continuing, as shown in FIG. 42B, the metal film 64 is formed on the front surface
of the insulating film 76, the inner wall (the side wall and the bottom portion) of
the first opening 76a, and the inner wall (the side wall and the bottom portion) of
the second opening 76b.
[0271] Then, the resist 81 is formed selectively on the metal film 64; and Cu electroplating
is performed using the metal film 64 as a current path. Thereby, the p-side interconnect
layer 65 and the n-side interconnect layer 66 are formed selectively on the metal
film 64.
[0272] Continuing as shown in FIGS. 43A and 43B, the resist 82 for forming the metal pillars
is formed. Then, Cu electroplating using the metal film 64 as a current path is performed
using the resist 82 as a mask. Thereby, the p-type metal pillar 67 is formed on the
p-side interconnect layer 65; and the n-side metal pillar 68 is formed on the n-side
interconnect layer 66.
[0273] The resist 82 is removed as shown in FIG. 44B using, for example, a solvent or oxygen
plasma. Subsequently, the exposed portion of the metal film 64 used as the seed metal
is removed by wet etching. Thereby, as shown in FIG. 44B, the electrical connection
by means of the metal film 64 between the p-side interconnect layer 65 and the n-side
interconnect layer 66 is broken.
[0274] Then, as shown in FIGS. 45A and 45B, after forming the resin layer 77 covering the
p-side interconnect layer 65, the n-side interconnect layer 66, the p-type metal pillar
67, and the n-side metal pillar 68, the resin layer 77 is polished to expose the end
surface (the p-side external terminal 67a) of the p-type metal pillar 67 and the end
surface (the n-side external terminal 68a) of the n-side metal pillar 68 from the
resin layer 77.
[0275] Continuing as shown in FIG. 46A, the substrate 10 is removed. In the case where the
substrate 10 is the sapphire substrate, the substrate 10 can be removed by, for example,
laser lift-off. In the case where the substrate 10 is the silicon substrate, the substrate
10 can be removed by etching.
[0276] As shown in FIG. 46B, the phosphor layer 50 is formed on the first surface 15a exposed
by the removal of the substrate 10. The polishing process of the resin layer 77 described
above may be performed after the removal process of the substrate 10 and may be performed
after the formation of the phosphor layer 50.
[0277] Then, singulation into the multiple semiconductor light emitting devices 5 is performed
as shown in FIGS. 47A and 47B by cutting the resin layer 77, the insulating film 76,
the insulating film 71, the first semiconductor layer 11, and the phosphor layer 50
at the position of the trench 73 shown in FIG. 37A.
[0278] In the embodiment as well, because each of the processes described above until the
dicing is performed can be performed collectively in the wafer state, it is unnecessary
to perform the interconnects and the packaging for every singulated individual device;
and it becomes possible to drastically reduce the production costs. In other words,
the interconnects and the packaging are already complete in the singulated state.
Therefore, the productivity can be increased; and as a result, price reductions become
easy.
[0279] FIG. 35 shows a modification of the semiconductor light emitting devices of the third
to fifth embodiments and corresponds to one chip region of the plan view of FIG. 25A.
[0280] In other words, in the structure of FIG. 35 similarly to the first and second embodiments
described above, the p-side region 80a, the light emitting layer 13, and the second
semiconductor layer 12 exist completely around the n-side regions 80b and the n-side
electrodes 61 provided on the n-side regions 80b.
[0281] Accordingly, the current spreads from one n-side electrode 61 to the entire peripheral
region of the one n-side electrode 61; and the current can be supplied efficiently
to the entire region of the light emitting layer 13. Accordingly, the entire region
of the light emitting layer 13 can be efficiently caused to emit light.
Sixth embodiment
[0282] FIG. 48 is a schematic cross-sectional view of a semiconductor light emitting device
6 of a sixth embodiment.
[0283] FIG. 50C is a schematic plan view of the semiconductor light emitting device 6 of
the sixth embodiment; and FIG. 48 corresponds to the F-F' cross section of FIG. 50C.
[0284] FIG. 49A to FIG. 50B are schematic plan views of the components of the semiconductor
light emitting device 6 of the sixth embodiment on the second surface side.
[0285] Similarly to the embodiment recited above, the semiconductor light emitting device
6 of the sixth embodiment includes the semiconductor layer 15. The semiconductor layer
15 includes the first semiconductor layer 11, the second semiconductor layer 12, and
the light emitting layer 13.
[0286] The first semiconductor layer 11 including the n-type GaN layer has the first surface
15a and the second surface provided on the side opposite to the first surface 15a.
As shown in FIG. 49A, the second surface has the p-side region 80a and the n-side
regions 80b.
[0287] The light emitting layer (the active layer) 13 is provided on the p-side region 80a
at the second surface of the first semiconductor layer 11; and the second semiconductor
layer 12 including the p-type GaN layer is provided on the light emitting layer 13.
The light emitting layer 13 is provided between the first semiconductor layer 11 and
the second semiconductor layer 12.
[0288] The light emitting layer 13 and the second semiconductor layer 12 are not provided
in the n-side regions 80b at the second surface of the first semiconductor layer 11.
[0289] The p-side electrode 62 is provided on the front surface of the second semiconductor
layer 12. The n-side electrodes 61 are provided on the n-side regions 80b at the second
surface of the first semiconductor layer 11.
[0290] The n-side regions 80b are formed by the front surface of the first semiconductor
layer 11 being exposed by selectively removing a portion of the light emitting layer
13 and the second semiconductor layer 12 formed on the entire surface of the second
surface of the first semiconductor layer 11.
[0291] As shown in FIG. 49A, the n-side regions 80b are formed in multiple locations (e.g.,
two locations) for every one chip. As shown in FIG. 49B, the n-side electrodes 61
are provided respectively on the n-side regions 80b.
[0292] The p-side electrode 62 is provided also on the second semiconductor layer 12 provided
between the two n-side electrodes 61. The p-side electrode 62 is provided on the region
including the light emitting layer 13; and the n-side electrodes 61 are provided on
the n-side regions 80b not including the light emitting layer 13.
[0293] The insulating film 71 is provided on the p-side electrode 62. The insulating film
71 is provided also on the side surfaces of the n-side electrodes 61, the side surface
of the light emitting layer 13, the side surface of the second semiconductor layer
12, and the side surface of the p-side electrode 62.
[0294] The p-side electrode 62 contacts the second semiconductor layer 12 and includes a
contact layer including, for example, at least one selected from nickel (Ni), gold
(Au), and rhodium (Rh) that is capable of forming an alloy with the gallium (Ga) included
in the second semiconductor layer 12. The p-side electrode 62 further includes a reflective
layer that is provided on the contact layer, has a reflectance for the light emitted
by the light emitting layer 13 that is higher than that of the contact layer, and
includes, for example, silver (Ag) as the main component.
[0295] The p-side interconnect layer 65 and the n-side interconnect layer 66 are provided
to be separated from each other on the insulating film 71 with the metal film 64 interposed
between the insulating film 71 and the p-side interconnect layer 65 and between the
insulating film 71 and the n-side interconnect layer 66.
[0296] The planar layout of the p-side interconnect layer 65 and the n-side interconnect
layer 66 is shown in FIG. 50A.
[0297] Similarly to the embodiment recited above, the p-side interconnect layer 65 and the
n-side interconnect layer 66 are formed by electroplating. The metal film 64 is used
as the seed metal in the plating.
[0298] A first opening 71a is made in the insulating film 71 to reach the p-side electrode
62 as shown in FIG. 49C; and the p-side interconnect layer 65 is electrically connected
to the p-side electrode 62 by means of a p-side via 65a (shown in FIG. 48) provided
inside the first opening 71a.
[0299] Second openings 71b are made in the insulating film 71 to reach the n-side electrodes
61 as shown in FIG. 49C; and the n-side interconnect layer 66 is electrically connected
to the n-side electrodes 61 by means of n-side vias 66a (shown in FIG. 48) provided
inside the second openings 71b.
[0300] The n-side interconnect layer 66 is provided also on the insulating film 71 on the
semiconductor layer 15 between two n-side electrodes 61.
[0301] The p-type metal pillar 67 is provided on the p-side interconnect layer 65. The n-side
metal pillar 68 is provided on the n-side interconnect layer 66.
[0302] The planar layout of the p-type metal pillar 67 and the n-side metal pillar 68 is
shown in FIG. 50B.
[0303] The p-side interconnect layer 65 and the p-type metal pillar 67 are included in the
p-side interconnect unit of the embodiment. The n-side interconnect layer 66 and the
n-side metal pillar 68 are included in the n-side interconnect unit of the embodiment.
[0304] The resin layer 77 is stacked on the insulating film 71. The resin layer 77 covers
the periphery of the p-side interconnect unit and the periphery of the n-side interconnect
unit. Also, the resin layer 77 is filled between the p-type metal pillar 67 and the
n-side metal pillar 68.
[0305] In the sixth embodiment as well, a high light output can be obtained by the light
emitting layer 13 formed over the region that is larger than the n-side electrodes
61. Further, the n-side electrodes 61 provided in the region that is narrower than
the region including the light emitting layer 13 are drawn out to the mounting surface
side as the n-side interconnect layer 66 that has a larger surface area.
[0306] The p-side electrode 62 is connected to the p-type metal pillar 67 including the
external terminal 67a of the mounting via a single-layer interconnect (the p-side
interconnect layer 65). The n-side electrodes 61 are connected to the n-type metal
pillar 68 including the external terminal 68a of the mounting via a single-layer interconnect
(the n-side interconnect layer 66).
[0307] The phosphor layer 50 is provided on the first surface 15a. The phosphor layer 50
includes the transparent resin 51 as a transparent medium and the phosphor 52 having
a multiple particle configuration dispersed in the transparent resin 51.
[0308] In the semiconductor light emitting device 6 of the sixth embodiment as well, the
light extraction from the first surface 15a is not impeded by the electrodes because
the p-side electrode 62 and the n-side electrodes 61 are provided at the second surface
on the side opposite to the first surface 15a which is the main extraction surface
of the light.
[0309] The n-side regions 80b at the second surface of the first semiconductor layer 11
and the n-side electrodes 61 provided on the n-side regions 80b are interspersed at
the second surface in a dot configuration or an island configuration. Therefore, the
uniform current distribution in the surface direction of the light emitting layer
13 can be realized while increasing the light emission surface area by reducing the
region not including the light emitting layer 13.
[0310] As shown in FIG. 49B, the p-side electrode 62 that is highly reflective to the light
emitted by the light emitting layer 13 spreads over substantially the entire surface
of the second surface. Accordingly, the reflecting surface area of the light radiated
from the light emitting layer 13 to the side opposite to the light extraction surface
(the first surface 15a) can be large; and a high light extraction efficiency is obtained.
[0311] As shown in FIG. 48 and FIGS. 49A and 49B, the light emitting layer 13 and the p-side
electrode 62 exist completely around the n-side regions 80b and the n-side electrodes
61. Accordingly, the current from one n-side electrode 61 spreads 360 degrees around
the one n-side electrode 61; and the current can be supplied efficiently to the entire
region of the light emitting layer 13. Accordingly, according to the embodiment, the
entire region of the light emitting layer 13 can be efficiently caused to emit light.
[0312] The transparent electrode may be provided between the second semiconductor layer
12 and the p-side electrode 62 in the structure of the sixth embodiment as in the
fifth embodiment described above. By controlling the thickness of the transparent
electrode such that the distance between the light emitting layer 13 and the p-side
electrode 62 is 1/2 of the light emission wavelength of the light emitting layer 13,
the reflection loss due to interference can be suppressed; and a high reflection efficiency
is obtained.
Seventh embodiment
[0313] FIGS. 51A to 51D are schematic plan views of the components of the semiconductor
light emitting device 7 of the seventh embodiment on the second surface side.
[0314] In the semiconductor light emitting device 7 of the seventh embodiment, the planar
layout of the p-side region 80a, the n-side regions 80b, the p-side electrode 62,
the n-side electrodes 61, the p-side interconnect layer 65, the n-side interconnect
layer 66, the p-type metal pillar 67, and the n-side metal pillar 68 is different
from that of the semiconductor light emitting device 6 of the sixth embodiment recited
above.
[0315] FIG. 51A corresponds to FIG. 49B of the sixth embodiment recited above and shows
the planar layout of the p-side electrode 62 and the n-side electrodes 61 of the semiconductor
light emitting device 7 of the seventh embodiment.
[0316] FIG. 51B corresponds to FIG. 49C of the sixth embodiment recited above and is a plan
view of the insulating film 71 and the openings 71a and 71b of the semiconductor light
emitting device 7 of the seventh embodiment.
[0317] FIG. 51C corresponds to FIG. 50A of the sixth embodiment recited above and shows
the planar layout of the p-side interconnect layer 65 and the n-side interconnect
layer 66 of the semiconductor light emitting device 7 of the seventh embodiment.
[0318] FIG. 51D corresponds to FIG. 50B of the sixth embodiment recited above and shows
the planar layout of the p-type metal pillar 67 and the n-side metal pillar 68 of
the semiconductor light emitting device 7 of the seventh embodiment.
[0319] Similarly to the embodiment recited above, the n-side regions 80b are formed by the
front surface of the first semiconductor layer 11 being exposed by selectively removing
a portion of the light emitting layer 13 and the second semiconductor layer 12 formed
on the entire surface of the second surface of the first semiconductor layer 11.
[0320] The n-side regions 80b are formed in multiple locations for every one chip. In the
embodiment, for example, four n-side regions 80b are formed at four corners of the
chip. Then, the n-side electrodes 61 are provided respectively on the n-side regions
80b. The p-side electrode 62 is provided between the n-side electrodes 61 when viewed
in plan in FIG. 51A.
[0321] Then, similarly to the embodiment recited above, the p-side interconnect layer 65
and the n-side interconnect layer 66 are provided to be separated from each other
on the insulating film 71 as shown in FIG. 51C.
[0322] The first opening 71a is made in the insulating film 71 to reach the p-side electrode
62 as shown in FIG. 51B; and the p-side interconnect layer 65 is electrically connected
to the p-side electrode 62 by means of a p-side via provided inside the first opening
71a.
[0323] The second openings 71b are made in the insulating film 71 to reach the n-side electrodes
61 as shown in FIG. 51B; and the n-side interconnect layer 66 is electrically connected
to the n-side electrodes 61 by means of n-side vias provided inside the second openings
71b.
[0324] The multiple n-side electrodes 61 are separated from each other without being linked
on the second surface. The multiple n-side electrodes 61 are connected to a common
n-side interconnect layer 66 spreading on the insulating film 71.
[0325] As shown in FIG. 51D, the p-type metal pillar 67 is provided on the p-side interconnect
layer 65; and the n-side metal pillar 68 is provided on the n-side interconnect layer
66.
[0326] The p-side electrode 62 is connected to the p-type metal pillar 67 via a single-layer
interconnect (the p-side interconnect layer 65). The n-side electrodes 61 are connected
to the n-type metal pillar 68 via a single-layer interconnect (the n-side interconnect
layer 66).
[0327] In the seventh embodiment as well, a high light output can be obtained by the light
emitting layer 13 formed over the region that is larger than the n-side electrodes
61. Further, the n-side electrodes 61 provided in the region that is narrower than
the region including the light emitting layer 13 are drawn out to the mounting surface
side as the n-side interconnect layer 66 that has a larger surface area.
[0328] The n-side regions 80b and the n-side electrodes 61 provided on the n-side regions
80b are interspersed at the second surface in a dot configuration or an island configuration.
Therefore, a uniform current distribution in the surface direction of the light emitting
layer 13 can be realized while increasing the light emission surface area by reducing
the region not including the light emitting layer 13.
[0329] As shown in FIG. 51A, the p-side electrode 62 that is highly reflective to the light
emitted by the light emitting layer 13 spreads over substantially the entire surface
of the second surface other than the four corners. Accordingly, the reflecting surface
area of the light radiated from the light emitting layer 13 to the side opposite to
the light extraction surface (the first surface 15a) can be large; and a high light
extraction efficiency is obtained.
[0330] FIGS. 52A to 52D are schematic plan views showing a modification of the planar layout
of the components of the semiconductor light emitting device 3 of the third embodiment
described above on the second surface side.
[0331] FIG. 52A corresponds to FIG. 25A recited above and shows the planar layout of the
p-side electrode 62, the n-side electrodes 61, and the n-side reflecting electrode
63.
[0332] FIG. 52B corresponds to FIG. 26A recited above and is a plan view of the insulating
film 76 and the openings 76a and 76b.
[0333] FIG. 52C corresponds to FIG. 27A recited above and shows the planar layout of the
p-side interconnect layer 65 and the n-side interconnect layer 66.
[0334] FIG. 52D corresponds to FIG. 29A recited above and shows the planar layout of the
p-type metal pillar 67 and the n-side metal pillar 68.
[0335] In the modification as well, the n-side regions 80b are formed in multiple locations
(e.g., three locations) for every one chip; and the n-side electrodes 61 are provided
respectively on the n-side regions 80b. The three n-side electrodes 61 are arranged,
for example, in the longitudinal direction (the X direction of FIG. 25A) of the chip.
[0336] The modification differs from the third embodiment recited above in that the p-side
electrode 62 is divided into two by the n-side reflecting electrode 63 inside one
chip as shown in FIG. 52A. The n-side reflecting electrode 63 is provided on the n-side
electrodes 61 and on the light emitting layer 13 between the n-side electrodes 61.
[0337] As shown in FIG. 52B, one (second) opening 76b and two (first) p-side openings 76a
are made in the insulating film 76 provided on the p-side electrodes 62 and the n-side
reflecting electrode 63.
[0338] The opening 76b communicates with the n-side reflecting electrode 63 formed on the
n-side reflecting electrode 63. The openings 76a are made respectively on the two
p-side electrodes 62 divided by the n-side reflecting electrode 63; and the openings
76a communicate with the p-side electrodes 62.
[0339] As shown in FIG. 52C, the p-side interconnect layer 65 and the n-side interconnect
layer 66 are provided to be separated from each other on the insulating film 76.
[0340] The p-side interconnect layer 65 is electrically connected to the p-side electrodes
62 by means of p-side vias provided inside the openings 76a made in the insulating
film 76. The n-side interconnect layer 66 is electrically connected to the n-side
reflecting electrode 63 and the n-side electrodes 61 by means of an n-side via provided
inside the opening 76b made in the insulating film 76.
[0341] As shown in FIG. 52D, the p-type metal pillar 67 is provided on the p-side interconnect
layer 65; and the n-side metal pillar 68 is provided on the n-side interconnect layer
66.
[0342] In the modification as well, a high light output can be obtained by the light emitting
layer 13 formed over the region that is larger than the n-side electrodes 61. Further,
the n-side electrodes 61 provided in the region that is narrower than the region including
the light emitting layer 13 are drawn out to the mounting surface side as the n-side
interconnect layer 66 that has a larger surface area.
[0343] The n-side regions 80b and the n-side electrodes 61 provided on the n-side regions
80b are interspersed at the second surface in a dot configuration or an island configuration.
Therefore, a uniform current distribution in the surface direction of the light emitting
layer 13 can be realized while increasing the light emission surface area by reducing
the region not including the light emitting layer 13.
[0344] As shown in FIG. 52A, the p-side electrode 62 and the n-side reflecting electrode
63 that are highly reflective to the light emitted by the light emitting layer 13
spread over substantially the entire surface on the side opposite to the light extraction
surface (the first surface 15a). Accordingly, the reflecting surface area of the light
radiated from the light emitting layer 13 to the side opposite to the light extraction
surface (the first surface 15a) can be large; and a high light extraction efficiency
is obtained.
[0345] While certain embodiments have been described, these embodiments have been presented
by way of example only, and are not intended to limit the scope of the inventions.
Indeed, the novel embodiments described herein may be embodied in a variety of other
forms; furthermore, various omissions, substitutions and changes in the form of the
embodiments described herein may be made without departing from the spirit of the
inventions. The accompanying claims and their equivalents are intended to cover such
forms or modification as would fall within the scope and spirit of the inventions.